This work is devoted to studying the magnon-magnon interaction effect in a two-dimensional checkerboard ferromagnet with the Dzyaloshinskii-Moriya interaction.Using a first-order Green function method,we analyze the i...This work is devoted to studying the magnon-magnon interaction effect in a two-dimensional checkerboard ferromagnet with the Dzyaloshinskii-Moriya interaction.Using a first-order Green function method,we analyze the influence of magnon-magnon interaction on the magnon band topology.We find that Chern numbers of two renormalized magnon bands are different above and below the critical temperature,which means that the magnon band gap-closing phenomenon is an indicator for one topological phase transition of the checkerboard ferromagnet.Our results show that the checkerboard ferromagnet possesses two topological phases,and its topological phase can be controlled either via the temperature or the applied magnetic field due to magnon-magnon interactions.Interestingly,it is found that the topological phase transition can occur twice with the increase in the temperature,which is different from the results of the honeycomb ferromagnet.展开更多
We show that a suitable combination of flat-band ferromagnetism,geometry and nontrivial electronic band topology can give rise to itinerant topological magnons.An SU(2) symmetric topological Hubbard model with nearly ...We show that a suitable combination of flat-band ferromagnetism,geometry and nontrivial electronic band topology can give rise to itinerant topological magnons.An SU(2) symmetric topological Hubbard model with nearly flat electronic bands,on a Kagome lattice,is considered as the prototype.This model exhibits ferromagnetic order when the lowest electronic band is half-filled.Using the numerical exact diagonalization method with a projection onto this nearly flat band,we can obtain the magnonic spectra.In the flat-band limit,the spectra exhibit distinct dispersions with Dirac points,similar to those of free electrons with isotropic hoppings,or a local spin magnet with pure ferromagnetic Heisenberg exchanges on the same geometry.Significantly,the non-flatness of the electronic band may induce a topological gap at the Dirac points,leading to a magnonic band with a nonzero Chern number.More intriguingly,this magnonic Chern number changes its sign when the topological index of the electronic band is reversed,suggesting that the nontrivial topology of the magnonic band is related to its underlying electronic band.Our work suggests interesting directions for the further exploration of,and searches for,itinerant topological magnons.展开更多
We study the topological properties of magnon excitations in a wide class of three-dimensional （3D） honeycomb lattices with ferromagnetic ground states. It is found that they host nodal ring magnon excitations. Thes...We study the topological properties of magnon excitations in a wide class of three-dimensional （3D） honeycomb lattices with ferromagnetic ground states. It is found that they host nodal ring magnon excitations. These rings locate on the same plane in the momentum space. The nodal ring degeneracy can be lifted by the Dzyaloshinskii- Moriya interactions to form two Weyl points with opposite charges. We explicitly discuss these physics in the simplest 3D honeycomb lattice and the hyperhoneycomb lattice, and show drumhead and are surface states in the nodal ring and Weyl phases, respectively, due to the bulk-boundary correspondence.展开更多
In this paper, we conduct an investigation into magnon self-squeezing states in a ferromagnet. In these states, the quantum fluctuations of the spin components can be lower than the zero-point quantum fluctuations of ...In this paper, we conduct an investigation into magnon self-squeezing states in a ferromagnet. In these states, the quantum fluctuations of the spin components can be lower than the zero-point quantum fluctuations of the coherent states. Through calculating the expectation values of spin fluctuations we gain the condition of achieving magnon self-squeezing. We introduce the mean-field theory for dealing with the nonlinear interaction term of Hamiltonian of magnon system.展开更多
The magnons(the quanta of collective spin-wave excitations)in two-dimensional van der Waals(vd W)magnets exhibit some intriguing characteristics,such as spin Nernst effect,topological magnons,Weyl magnons,moiréma...The magnons(the quanta of collective spin-wave excitations)in two-dimensional van der Waals(vd W)magnets exhibit some intriguing characteristics,such as spin Nernst effect,topological magnons,Weyl magnons,moirémagnons,magnon valley Hall effect,etc.,and can be regulated through approaches such as stacking,electric doping,pressure,strain and twisting,opening unprecedented avenues to explore fundamental magnetic physics and spin-based technologies.Over the past few years,intense research efforts have been invested in unraveling magnon properties in vd W materials.This review comprehensively summarizes recent advancements in understanding magnons in vd W magnetic systems,spanning fundamental theories and experimental frontiers.It also introduces the experimental techniques widely used in this field,including inelastic neutron scattering,Raman/Brillouin spectroscopy,time-resolved spectroscopy and inelastic magnetotunneling spectroscopy,and discusses the coupling between magnons and other excitations,such as phonons and excitons.展开更多
Strong coupling effects in magnonic systems are highly promising.They combine the advantages of different quasiparticles and enable energy transfer for coherent information processing.When driven by microwave,electric...Strong coupling effects in magnonic systems are highly promising.They combine the advantages of different quasiparticles and enable energy transfer for coherent information processing.When driven by microwave,electric,or optical pumps,these coupling effects can give rise to intriguing nonlinear phenomena,which have become a focal point in the field of magnonics.This review systematically explores pump-engineered magnon-coupling systems from three perspectives:(1)pump-induced hybridization of magnon modes,(2)nonlinear manipulation of magnon dynamics,and(3)implementation of functional magnonic devices.Unlike conventional cavity-magnon interactions that are constrained by electromagnetic boundaries,pumped coupled magnons are liberated from these restrictions.They can operate over a broad frequency band rather than being confined to discrete modes.An example is the recently discovered pump-induced magnon mode(PIM).These magnons arise from the collective excitations of unsaturated spins driven by microwave pumps.They exhibit reduced damping and photon-number-sensitive splitting characteristics,facilitating waveform-controlled coupling strength and enhanced nonlinearity—features that support phenomena such as magnonic frequency combs(MFCs).By expanding this principle to electric pumping schemes,we bridge fundamental physics and practical device applications,enabling nonreciprocal switching and meter-scale strong coupling.These advances establish high-dimensional control capabilities for coupled magnonics and pave the way for their use as a promising platform for dynamically programmable devices,magnetic-field sensing,and coherent networks.展开更多
Thermoelectric materials,capable of converting temperature gradients into electrical power,have been traditionally limited by a trade-off between thermopower and electrical conductivity.This study introduces a novel,b...Thermoelectric materials,capable of converting temperature gradients into electrical power,have been traditionally limited by a trade-off between thermopower and electrical conductivity.This study introduces a novel,broadly applicable approach that enhances both the spin-driven thermopower and the thermoelectric figure-of-merit(zT)without compromising electrical conductivity,using temperature-driven spin crossover.Our approach,supported by both theoretical and experimental evidence,is demonstrated through a case study of chromium doped-manganese telluride,but is not confined to this material and can be extended to other magnetic materials.By introducing dopants to create a high crystal field and exploiting the entropy changes associated with temperature-driven spin crossover,we achieved a significant increase in thermopower,by approximately 136μV K^(-1),representing more than a 200%enhancement at elevated temperatures within the paramagnetic domain.Our exploration of the bipolar semiconducting nature of these materials reveals that suppressing bipolar magnon/paramagnon-drag thermopower is key to understanding and utilizing spin crossover-driven thermopower.These findings,validated by inelastic neutron scattering,X-ray photoemission spectroscopy,thermal transport,and energy conversion measurements,shed light on crucial material design parameters.We provide a comprehensive framework that analyzes the interplay between spin entropy,hopping transport,and magnon/paramagnon lifetimes,paving the way for the development of high-performance spin-driven thermoelectric materials.展开更多
Altermagnets,a new type of collinear antiferromagnet,exhibiting non-degenerate electron and magnon dispersion in momentum space have attracted intensive research attention.We theoretically analyze the origin and featu...Altermagnets,a new type of collinear antiferromagnet,exhibiting non-degenerate electron and magnon dispersion in momentum space have attracted intensive research attention.We theoretically analyze the origin and feature of chiral magnon splitting in representative altermagnets including tetragonal RuO_(2),hexagonal MnTe,and orthorhombic LaMnO_(3).The magnon spin transport properties including spin Seebeck and spin Nernst coefcients have been investigated.Through these materials,we demonstrate the diference of chiral splitting in d-wave and g-wave antiferromagnet on magnon transport.RuO2with planar magnon splitting exhibits signifcant magnon spin Nernst and magnon spin Seebeck anisotropy in(110)and(001)planes,whereas MnTe,due to its bulk-like magnon splitting,is incapable of producing magnon spin Nernst efect.Our work may provide in-depth understanding on the mechanisms of nonrelativistic magnon splitting and thermal spin transport in altermagnets.展开更多
Dispersion characteristics of magnonic crystals have attracted considerable attention because of the potential applications for spin-wave devices.In this work,we investigated the strain-manipulated dispersion characte...Dispersion characteristics of magnonic crystals have attracted considerable attention because of the potential applications for spin-wave devices.In this work,we investigated the strain-manipulated dispersion characteristics of magnonic crystals with Dzyaloshinskii–Moriya interaction(DMI)and discussed the potential applications in spin-wave devices.Here,the ground states and stabilities of the magnonic crystals were investigated.Then,the strain-manipulated dispersion characteristics of the magnonic crystals based on domains and skyrmions were studied.The simulation results indicated that,the applied strain could manipulate the band widths and the positions of the allowed frequency bands.Finally,the realization of magnonic crystal heterojunctions and potential applications in spin-wave devices,such as filters,diodes,and transistors based on strain-manipulated magnonic crystals were proposed.Our research provides a theoretical foundation for designing tunable spin-wave devices based on strain-manipulated magnonic crystals with DMI.展开更多
We investigate magnonic topology in the breathing Su–Schrieffer–Heeger(SSH) model, incorporating non-Hermitian effects. Our results demonstrate the coexistence of first-and second-order magnonic topologies, with non...We investigate magnonic topology in the breathing Su–Schrieffer–Heeger(SSH) model, incorporating non-Hermitian effects. Our results demonstrate the coexistence of first-and second-order magnonic topologies, with non-Hermitian effects exhibiting size-dependent behavior. In two-dimensional systems, non-Hermitian terms induce a flat band and gap closure along high-symmetry paths, whereas in one-dimensional systems, a finite band gap persists for small system sizes. Additionally, the corner states remain robust, and a pronounced non-Hermitian skin effect emerges. Our findings provide new insights into magnon-based devices, emphasizing the impact of non-Hermitian effects on their design and functionality.展开更多
We utilize conventional wave-vector-resolved Brillouin light scattering technology to investigate the spin wave response in YIG thin films under high-power microwave excitation. By varying the microwave frequency, ext...We utilize conventional wave-vector-resolved Brillouin light scattering technology to investigate the spin wave response in YIG thin films under high-power microwave excitation. By varying the microwave frequency, external bias magnetic field, and in-plane wave vector, in addition to observing the dipole-exchange spin waves excited by parallel parametric pumping, we further observe broadband spin wave excitation within the dipole-exchange spin wave spectrum. This broadband excitation results from the combined effects of parallel and perpendicular parametric pumping, induced by irregularities in the excitation geometry, as well as magnon–magnon scattering arising from the absence of certain spin wave modes. Our findings offer new insights into the mechanisms of energy dissipation and relaxation processes caused by spin wave excitation in magnetic devices operating at high power.展开更多
We report the bifurcation of bound states in the continuum(BICs) in a dissipative cavity magnonic system, where a BIC splits into a pair of BICs. We theoretically analyze BICs in a dissipative cavity magnonic system a...We report the bifurcation of bound states in the continuum(BICs) in a dissipative cavity magnonic system, where a BIC splits into a pair of BICs. We theoretically analyze BICs in a dissipative cavity magnonic system and derive the critical condition for BICs bifurcation. Based on the theoretical results, we experimentally tune the dissipative photon–magnon coupling strength and demonstrate precise control over the detuning and number of BICs. When the dissipative coupling strength reaches a critical value, we observe the bifurcation of BICs, which is consistent with the theoretical prediction. Our systematic investigation of the evolution of BICs concerning the dissipative coupling strength and the discovery of the BIC bifurcation may enhance the sensitivity of BICs to external perturbations, potentially enabling applications in ultrasensitive detection.展开更多
Interlayer interactions in bilayer or multilayer electron systems have been studied extensively,and many exotic physical phenomena have been revealed.However,systematic investigations of the impact of interlayer inter...Interlayer interactions in bilayer or multilayer electron systems have been studied extensively,and many exotic physical phenomena have been revealed.However,systematic investigations of the impact of interlayer interactions on magnonic physics are very few.Here,we use a van derWaals(vdW)honeycomb heterostructure as a platform to investigate the modulation of magnon properties in honeycomb AA-and AB-stacking heterostructures with ferromagnetic and antiferromagnetic interlayer interactions,including topological phases and thermal Hall conductivity.Our results reveal that interlayer interactions play a crucial role in modulating the magnonic topology and Hall transport properties of magnetic heterostructures,with potential for experimental realization.展开更多
Microwave–optical entanglement is essential for efficient quantum communication,secure information transfer,and integrating microwave and optical quantum systems to advance hybrid quantum technologies.In this work,we...Microwave–optical entanglement is essential for efficient quantum communication,secure information transfer,and integrating microwave and optical quantum systems to advance hybrid quantum technologies.In this work,we demonstrate how the magnon Kerr effect can be harnessed to generate and control nonreciprocal entanglement in cavity optomagnomechanics(COMM).This effect induces magnon frequency shifts and introduces pair-magnon interactions,both of which are tunable through the magnetic field direction,enabling nonreciprocal behavior.By adjusting system parameters such as magnon frequency detuning,we show that magnon–phonon,microwave–optical photon–photon,and optical photon–magnon entanglement can be nonreciprocally enhanced and rendered more robust against thermal noise.Additionally,the nonreciprocity of entanglement can be selectively controlled,and ideal nonreciprocal entanglement is achievable.This work paves the way for designing nonreciprocal quantum devices across the microwave and optical regimes,leveraging the unique properties of the magnon Kerr effect in COMM.展开更多
A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise...A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.展开更多
We present protocols to generate quantum entanglement on nonlocal magnons in hybrid systems composed of yttrium iron garnet(YIG)spheres,microwave cavities and a superconducting(SC)qubit.In the schemes,the YIGs are cou...We present protocols to generate quantum entanglement on nonlocal magnons in hybrid systems composed of yttrium iron garnet(YIG)spheres,microwave cavities and a superconducting(SC)qubit.In the schemes,the YIGs are coupled to respective microwave cavities in resonant way,and the SC qubit is placed at the center of the cavities,which interacts with the cavities simultaneously.By exchanging the virtual photon,the cavities can indirectly interact in the far-detuning regime.Detailed protocols are presented to establish entanglement for two,three and arbitrary N magnons with reasonable fidelities.展开更多
The generation and manipulation of strong entanglement and Einstein-Podolsky-Rosen(EPR)steering in macroscopic systems are outstanding challenges in modern physics.Especially,the observation of asymmetric EPR steering...The generation and manipulation of strong entanglement and Einstein-Podolsky-Rosen(EPR)steering in macroscopic systems are outstanding challenges in modern physics.Especially,the observation of asymmetric EPR steering is important for both its fundamental role in interpreting the nature of quantum mechanics and its application as resource for the tasks where the levels of trust at different parties are highly asymmetric.Here,we study the entanglement and EPR steering between two macroscopic magnons in a hybrid ferrimagnet—light system.In the absence of light,the two types of magnons on the two sublattices can be entangled,but no quantum steering occurs when they are damped with the same rates.In the presence of the cavity field,the entanglement can be significantly enhanced,and strong two-way asymmetric quantum steering appears between two magnons with equal dissipation.This is very different from the conventional protocols to produce asymmetric steering by imposing additional unbalanced losses or noises on the two parties at the cost of reducing steerability.The essential physics is well understood by the unbalanced population of acoustic and optical magnons under the cooling effect of cavity photons.Our finding may provide a novel platform to manipulate the quantum steering and the detection of bi-party steering provides a knob to probe the magnetic damping on each sublattice of a magnet.展开更多
Within the magnonics community,there has been a lot of interests in the magnon–skyrmion interaction.Magnons and skyrmions are two intriguing phenomena in condensed matter physics,and magnetic nanotubes have emerged a...Within the magnonics community,there has been a lot of interests in the magnon–skyrmion interaction.Magnons and skyrmions are two intriguing phenomena in condensed matter physics,and magnetic nanotubes have emerged as a suitable platform to study their complex interactions.We show that magnon frequency combs can be induced in magnetic nanotubes by three-wave mixing between the propagating magnons and skyrmion.This study enriches our fundamental comprehension of magnon–skyrmion interactions and holds promise for developing innovative spintronic devices and applications.This frequency comb tunability and unique spectral features offer a rich platform for exploring novel avenues in magnetic nanotechnology.展开更多
We theoretically investigate the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relation can be manipulated by strains through magneto-elastic coupling. ...We theoretically investigate the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relation can be manipulated by strains through magneto-elastic coupling. Especially, the allowed bands and forbidden bands in dispersion relations shift to higher frequency with strain changing from compressive to tensile,while shifting to lower frequency with strain changing from tensile to compressive. We also confirm that the spin wave with specific frequency can pass the magnonic crystal or be blocked by tuning the strains. The result provides an advanced platform for studying the tunable skyrmion-based spin wave devices.展开更多
Motivated by recent experimental progress on the quasi-one-dimensional quantum magnet Ni Nb2O6, we study the spin dynamics of an S = 1 ferromagnetic Heisenberg chain with single-ion anisotropy by using a semiclassical...Motivated by recent experimental progress on the quasi-one-dimensional quantum magnet Ni Nb2O6, we study the spin dynamics of an S = 1 ferromagnetic Heisenberg chain with single-ion anisotropy by using a semiclassical molecular dynamics approach. This system undergoes a quantum phase transition from a ferromagnetic to a paramagnetic state under a transverse magnetic field, and the magnetic response reflecting this transition is well described by our semiclassical method.We show that at low temperature the transverse component of the dynamical structure factor depicts clearly the magnon dispersion, and the longitudinal component exhibits two continua associated with single-and two-magnon excitations,respectively. These spin excitation spectra show interesting temperature dependence as effects of magnon interactions. Our findings shed light on the experimental detection of spin excitations in a large class of quasi-one-dimensional magnets.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.12064011)the Natural Science Fund Project of Hunan Province(Grant No.2020JJ4498)the Graduate Research Innovation Foundation of Jishou University(Grant No.Jdy21030).
文摘This work is devoted to studying the magnon-magnon interaction effect in a two-dimensional checkerboard ferromagnet with the Dzyaloshinskii-Moriya interaction.Using a first-order Green function method,we analyze the influence of magnon-magnon interaction on the magnon band topology.We find that Chern numbers of two renormalized magnon bands are different above and below the critical temperature,which means that the magnon band gap-closing phenomenon is an indicator for one topological phase transition of the checkerboard ferromagnet.Our results show that the checkerboard ferromagnet possesses two topological phases,and its topological phase can be controlled either via the temperature or the applied magnetic field due to magnon-magnon interactions.Interestingly,it is found that the topological phase transition can occur twice with the increase in the temperature,which is different from the results of the honeycomb ferromagnet.
基金Supported by the National Natural Science Foundation of China (Grant No.11774152)National Key R&D Program of China(Grant No.2016YFA0300401)。
文摘We show that a suitable combination of flat-band ferromagnetism,geometry and nontrivial electronic band topology can give rise to itinerant topological magnons.An SU(2) symmetric topological Hubbard model with nearly flat electronic bands,on a Kagome lattice,is considered as the prototype.This model exhibits ferromagnetic order when the lowest electronic band is half-filled.Using the numerical exact diagonalization method with a projection onto this nearly flat band,we can obtain the magnonic spectra.In the flat-band limit,the spectra exhibit distinct dispersions with Dirac points,similar to those of free electrons with isotropic hoppings,or a local spin magnet with pure ferromagnetic Heisenberg exchanges on the same geometry.Significantly,the non-flatness of the electronic band may induce a topological gap at the Dirac points,leading to a magnonic band with a nonzero Chern number.More intriguingly,this magnonic Chern number changes its sign when the topological index of the electronic band is reversed,suggesting that the nontrivial topology of the magnonic band is related to its underlying electronic band.Our work suggests interesting directions for the further exploration of,and searches for,itinerant topological magnons.
基金Supported by the National Basic Research Program of China under Grant No 2015CB921300the National Natural Science Foundation of China under Grant No 11334012the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB07000000
文摘We study the topological properties of magnon excitations in a wide class of three-dimensional （3D） honeycomb lattices with ferromagnetic ground states. It is found that they host nodal ring magnon excitations. These rings locate on the same plane in the momentum space. The nodal ring degeneracy can be lifted by the Dzyaloshinskii- Moriya interactions to form two Weyl points with opposite charges. We explicitly discuss these physics in the simplest 3D honeycomb lattice and the hyperhoneycomb lattice, and show drumhead and are surface states in the nodal ring and Weyl phases, respectively, due to the bulk-boundary correspondence.
基金The project supported by National Natural Science Foundation of China under Grant Nos .19847004 and 10474025
文摘In this paper, we conduct an investigation into magnon self-squeezing states in a ferromagnet. In these states, the quantum fluctuations of the spin components can be lower than the zero-point quantum fluctuations of the coherent states. Through calculating the expectation values of spin fluctuations we gain the condition of achieving magnon self-squeezing. We introduce the mean-field theory for dealing with the nonlinear interaction term of Hamiltonian of magnon system.
基金the Chinese Academy of Sciences—the Scientific and the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-120)the National Science Foundation of China(Grant No.NSFC12525405)。
文摘The magnons(the quanta of collective spin-wave excitations)in two-dimensional van der Waals(vd W)magnets exhibit some intriguing characteristics,such as spin Nernst effect,topological magnons,Weyl magnons,moirémagnons,magnon valley Hall effect,etc.,and can be regulated through approaches such as stacking,electric doping,pressure,strain and twisting,opening unprecedented avenues to explore fundamental magnetic physics and spin-based technologies.Over the past few years,intense research efforts have been invested in unraveling magnon properties in vd W materials.This review comprehensively summarizes recent advancements in understanding magnons in vd W magnetic systems,spanning fundamental theories and experimental frontiers.It also introduces the experimental techniques widely used in this field,including inelastic neutron scattering,Raman/Brillouin spectroscopy,time-resolved spectroscopy and inelastic magnetotunneling spectroscopy,and discusses the coupling between magnons and other excitations,such as phonons and excitons.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0580000)the National Natural Science Foundation of China(Grant Nos.12204306,12122413,12227901,12474120,and U23A6002)+4 种基金the Science and Technology Commission of Shanghai Municipality(Grant Nos.23JC1404100 and 22JC1403300)the National Key R&D Program of China(Grant Nos.2022YFA1404603 and2023YFA1406604)the Shandong Provincial Natural Science FoundationChina(Grant No.ZR2024YQ001)the Qilu Young Scholar Programs of Shandong University。
文摘Strong coupling effects in magnonic systems are highly promising.They combine the advantages of different quasiparticles and enable energy transfer for coherent information processing.When driven by microwave,electric,or optical pumps,these coupling effects can give rise to intriguing nonlinear phenomena,which have become a focal point in the field of magnonics.This review systematically explores pump-engineered magnon-coupling systems from three perspectives:(1)pump-induced hybridization of magnon modes,(2)nonlinear manipulation of magnon dynamics,and(3)implementation of functional magnonic devices.Unlike conventional cavity-magnon interactions that are constrained by electromagnetic boundaries,pumped coupled magnons are liberated from these restrictions.They can operate over a broad frequency band rather than being confined to discrete modes.An example is the recently discovered pump-induced magnon mode(PIM).These magnons arise from the collective excitations of unsaturated spins driven by microwave pumps.They exhibit reduced damping and photon-number-sensitive splitting characteristics,facilitating waveform-controlled coupling strength and enhanced nonlinearity—features that support phenomena such as magnonic frequency combs(MFCs).By expanding this principle to electric pumping schemes,we bridge fundamental physics and practical device applications,enabling nonreciprocal switching and meter-scale strong coupling.These advances establish high-dimensional control capabilities for coupled magnonics and pave the way for their use as a promising platform for dynamically programmable devices,magnetic-field sensing,and coherent networks.
基金funding support by the National Science Foundation(NSF)under grant numbers CBET-2110603the Air Force Office of Scientific Research(AFOSR)under contract number FA9550-12-1-0225supported by the State of North Carolina and the National Science Foundation(award number ECCS-2025064).
文摘Thermoelectric materials,capable of converting temperature gradients into electrical power,have been traditionally limited by a trade-off between thermopower and electrical conductivity.This study introduces a novel,broadly applicable approach that enhances both the spin-driven thermopower and the thermoelectric figure-of-merit(zT)without compromising electrical conductivity,using temperature-driven spin crossover.Our approach,supported by both theoretical and experimental evidence,is demonstrated through a case study of chromium doped-manganese telluride,but is not confined to this material and can be extended to other magnetic materials.By introducing dopants to create a high crystal field and exploiting the entropy changes associated with temperature-driven spin crossover,we achieved a significant increase in thermopower,by approximately 136μV K^(-1),representing more than a 200%enhancement at elevated temperatures within the paramagnetic domain.Our exploration of the bipolar semiconducting nature of these materials reveals that suppressing bipolar magnon/paramagnon-drag thermopower is key to understanding and utilizing spin crossover-driven thermopower.These findings,validated by inelastic neutron scattering,X-ray photoemission spectroscopy,thermal transport,and energy conversion measurements,shed light on crucial material design parameters.We provide a comprehensive framework that analyzes the interplay between spin entropy,hopping transport,and magnon/paramagnon lifetimes,paving the way for the development of high-performance spin-driven thermoelectric materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174129,T2394475,and T2394470)。
文摘Altermagnets,a new type of collinear antiferromagnet,exhibiting non-degenerate electron and magnon dispersion in momentum space have attracted intensive research attention.We theoretically analyze the origin and feature of chiral magnon splitting in representative altermagnets including tetragonal RuO_(2),hexagonal MnTe,and orthorhombic LaMnO_(3).The magnon spin transport properties including spin Seebeck and spin Nernst coefcients have been investigated.Through these materials,we demonstrate the diference of chiral splitting in d-wave and g-wave antiferromagnet on magnon transport.RuO2with planar magnon splitting exhibits signifcant magnon spin Nernst and magnon spin Seebeck anisotropy in(110)and(001)planes,whereas MnTe,due to its bulk-like magnon splitting,is incapable of producing magnon spin Nernst efect.Our work may provide in-depth understanding on the mechanisms of nonrelativistic magnon splitting and thermal spin transport in altermagnets.
文摘Dispersion characteristics of magnonic crystals have attracted considerable attention because of the potential applications for spin-wave devices.In this work,we investigated the strain-manipulated dispersion characteristics of magnonic crystals with Dzyaloshinskii–Moriya interaction(DMI)and discussed the potential applications in spin-wave devices.Here,the ground states and stabilities of the magnonic crystals were investigated.Then,the strain-manipulated dispersion characteristics of the magnonic crystals based on domains and skyrmions were studied.The simulation results indicated that,the applied strain could manipulate the band widths and the positions of the allowed frequency bands.Finally,the realization of magnonic crystal heterojunctions and potential applications in spin-wave devices,such as filters,diodes,and transistors based on strain-manipulated magnonic crystals were proposed.Our research provides a theoretical foundation for designing tunable spin-wave devices based on strain-manipulated magnonic crystals with DMI.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12347156, 12174157, 12074150, and 12174158)the National Key Research and Development Program of China (Grant No. 2022YFA1405200)+1 种基金the Natural Science Foundation of Jiangsu Province (Grant No. BK20230516)the Scientific Research Project of Jiangsu University (Grant No. 550171001)。
文摘We investigate magnonic topology in the breathing Su–Schrieffer–Heeger(SSH) model, incorporating non-Hermitian effects. Our results demonstrate the coexistence of first-and second-order magnonic topologies, with non-Hermitian effects exhibiting size-dependent behavior. In two-dimensional systems, non-Hermitian terms induce a flat band and gap closure along high-symmetry paths, whereas in one-dimensional systems, a finite band gap persists for small system sizes. Additionally, the corner states remain robust, and a pronounced non-Hermitian skin effect emerges. Our findings provide new insights into magnon-based devices, emphasizing the impact of non-Hermitian effects on their design and functionality.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 52471200, 12174165, and 52201219)。
文摘We utilize conventional wave-vector-resolved Brillouin light scattering technology to investigate the spin wave response in YIG thin films under high-power microwave excitation. By varying the microwave frequency, external bias magnetic field, and in-plane wave vector, in addition to observing the dipole-exchange spin waves excited by parallel parametric pumping, we further observe broadband spin wave excitation within the dipole-exchange spin wave spectrum. This broadband excitation results from the combined effects of parallel and perpendicular parametric pumping, induced by irregularities in the excitation geometry, as well as magnon–magnon scattering arising from the absence of certain spin wave modes. Our findings offer new insights into the mechanisms of energy dissipation and relaxation processes caused by spin wave excitation in magnetic devices operating at high power.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2023YFA1406604)the National Natural Science Foundation of China (Grant Nos. 12274260, 12204306, 12122413, and 12474120)+1 种基金the Shandong Provincial Natural Science Foundation, China (Grant No. ZR2024YQ001)the Qilu Young Scholar Programs of Shandong University。
文摘We report the bifurcation of bound states in the continuum(BICs) in a dissipative cavity magnonic system, where a BIC splits into a pair of BICs. We theoretically analyze BICs in a dissipative cavity magnonic system and derive the critical condition for BICs bifurcation. Based on the theoretical results, we experimentally tune the dissipative photon–magnon coupling strength and demonstrate precise control over the detuning and number of BICs. When the dissipative coupling strength reaches a critical value, we observe the bifurcation of BICs, which is consistent with the theoretical prediction. Our systematic investigation of the evolution of BICs concerning the dissipative coupling strength and the discovery of the BIC bifurcation may enhance the sensitivity of BICs to external perturbations, potentially enabling applications in ultrasensitive detection.
基金supported by the National Natural Science Foundation of China(Grant Nos.12404051,12347156,12174157,12074150,and 12174158)the National Key Research and Development Program of China(Grant No.2022YFA1405200)+2 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20230516)the Scientific Research Project of Jiangsu University(Grant No.550171001)support provided by the Deutsche Forschungsgemeinschaft(DFG,German Research Founda-tion)-TRR 288/2-422213477(project B06).
文摘Interlayer interactions in bilayer or multilayer electron systems have been studied extensively,and many exotic physical phenomena have been revealed.However,systematic investigations of the impact of interlayer interactions on magnonic physics are very few.Here,we use a van derWaals(vdW)honeycomb heterostructure as a platform to investigate the modulation of magnon properties in honeycomb AA-and AB-stacking heterostructures with ferromagnetic and antiferromagnetic interlayer interactions,including topological phases and thermal Hall conductivity.Our results reveal that interlayer interactions play a crucial role in modulating the magnonic topology and Hall transport properties of magnetic heterostructures,with potential for experimental realization.
基金supported by the Natural Science Foundation of Zhejiang Province(Grant No.LY24A040004)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Grant No.2025C01028)+2 种基金the Shenzhen International Quantum Academy(Grant No.SIQA2024KFKT010)YWW is supported by the Natural Science Foundation of Zhejiang Province(Grant No.LY23A40002)Wenzhou Science and Technology Plan Project(Grant No.L20240004).
文摘Microwave–optical entanglement is essential for efficient quantum communication,secure information transfer,and integrating microwave and optical quantum systems to advance hybrid quantum technologies.In this work,we demonstrate how the magnon Kerr effect can be harnessed to generate and control nonreciprocal entanglement in cavity optomagnomechanics(COMM).This effect induces magnon frequency shifts and introduces pair-magnon interactions,both of which are tunable through the magnetic field direction,enabling nonreciprocal behavior.By adjusting system parameters such as magnon frequency detuning,we show that magnon–phonon,microwave–optical photon–photon,and optical photon–magnon entanglement can be nonreciprocally enhanced and rendered more robust against thermal noise.Additionally,the nonreciprocity of entanglement can be selectively controlled,and ideal nonreciprocal entanglement is achievable.This work paves the way for designing nonreciprocal quantum devices across the microwave and optical regimes,leveraging the unique properties of the magnon Kerr effect in COMM.
基金funded by NSERC Discovery Grants, NSERC Discovery Accelerator Supplements, Innovation Proof-of-Concept Grant of Research Manitoba, and Faculty of Science Research Innovation and Commercialization Grant of University of Manitoba (C.-M.H.)。
文摘A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.12075159 and 12171044Beijing Natural Science Foundation(Grant No.Z190005)the Academician Innovation Platform of Hainan Province.
文摘We present protocols to generate quantum entanglement on nonlocal magnons in hybrid systems composed of yttrium iron garnet(YIG)spheres,microwave cavities and a superconducting(SC)qubit.In the schemes,the YIGs are coupled to respective microwave cavities in resonant way,and the SC qubit is placed at the center of the cavities,which interacts with the cavities simultaneously.By exchanging the virtual photon,the cavities can indirectly interact in the far-detuning regime.Detailed protocols are presented to establish entanglement for two,three and arbitrary N magnons with reasonable fidelities.
基金supported by the National Natural Science Foundation of China(Grant Nos.11975026,61475007,and 61704071)the National Key Research and Development Program of China(Grant Nos.2018YFB1107200,and 2016YFA0301302)+1 种基金the Key Research and Development Program of Guangzhou Province(Grant No.2018B030329001)the Beijing Natural Science Foundation(Grant No.Z190005)。
文摘The generation and manipulation of strong entanglement and Einstein-Podolsky-Rosen(EPR)steering in macroscopic systems are outstanding challenges in modern physics.Especially,the observation of asymmetric EPR steering is important for both its fundamental role in interpreting the nature of quantum mechanics and its application as resource for the tasks where the levels of trust at different parties are highly asymmetric.Here,we study the entanglement and EPR steering between two macroscopic magnons in a hybrid ferrimagnet—light system.In the absence of light,the two types of magnons on the two sublattices can be entangled,but no quantum steering occurs when they are damped with the same rates.In the presence of the cavity field,the entanglement can be significantly enhanced,and strong two-way asymmetric quantum steering appears between two magnons with equal dissipation.This is very different from the conventional protocols to produce asymmetric steering by imposing additional unbalanced losses or noises on the two parties at the cost of reducing steerability.The essential physics is well understood by the unbalanced population of acoustic and optical magnons under the cooling effect of cavity photons.Our finding may provide a novel platform to manipulate the quantum steering and the detection of bi-party steering provides a knob to probe the magnetic damping on each sublattice of a magnet.
基金supported by the National Key R&D Program China (Grant No.2022YFA1402802)the National Natural Science Foundation of China (Grant Nos.12374103 and 12074057)。
文摘Within the magnonics community,there has been a lot of interests in the magnon–skyrmion interaction.Magnons and skyrmions are two intriguing phenomena in condensed matter physics,and magnetic nanotubes have emerged as a suitable platform to study their complex interactions.We show that magnon frequency combs can be induced in magnetic nanotubes by three-wave mixing between the propagating magnons and skyrmion.This study enriches our fundamental comprehension of magnon–skyrmion interactions and holds promise for developing innovative spintronic devices and applications.This frequency comb tunability and unique spectral features offer a rich platform for exploring novel avenues in magnetic nanotechnology.
文摘We theoretically investigate the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relation can be manipulated by strains through magneto-elastic coupling. Especially, the allowed bands and forbidden bands in dispersion relations shift to higher frequency with strain changing from compressive to tensile,while shifting to lower frequency with strain changing from tensile to compressive. We also confirm that the spin wave with specific frequency can pass the magnonic crystal or be blocked by tuning the strains. The result provides an advanced platform for studying the tunable skyrmion-based spin wave devices.
基金Project supported by the National Key R&D Program of China (Grant No. 2023YFA1406500)the National Natural Science Foundation of China (Grant Nos. 12334008, 12174441,12134020, and 12374156)。
文摘Motivated by recent experimental progress on the quasi-one-dimensional quantum magnet Ni Nb2O6, we study the spin dynamics of an S = 1 ferromagnetic Heisenberg chain with single-ion anisotropy by using a semiclassical molecular dynamics approach. This system undergoes a quantum phase transition from a ferromagnetic to a paramagnetic state under a transverse magnetic field, and the magnetic response reflecting this transition is well described by our semiclassical method.We show that at low temperature the transverse component of the dynamical structure factor depicts clearly the magnon dispersion, and the longitudinal component exhibits two continua associated with single-and two-magnon excitations,respectively. These spin excitation spectra show interesting temperature dependence as effects of magnon interactions. Our findings shed light on the experimental detection of spin excitations in a large class of quasi-one-dimensional magnets.
