In this study,we calculated the photon absorption cross sections of even–even neodymium(Nd)isotopes using the Dirac Quasiparticle Finite Amplitude Method(relativistic QFAM),combined with the Tiny Smearing Approximati...In this study,we calculated the photon absorption cross sections of even–even neodymium(Nd)isotopes using the Dirac Quasiparticle Finite Amplitude Method(relativistic QFAM),combined with the Tiny Smearing Approximation(TSA)method.This approach enables the efficient reproduction of experimental photon absorption data for both spherical and deformed nuclei.We demonstrate that relativistic QFAM calculations with any smearing parameter γ can be scaled using the TSA method,significantly reducing the computational cost.Our method was applied to Nd isotopes,with experimental data reproduced for ^(142,144,146,148,150)Nd and predictions for ^(152)Nd.By optimizing the three key parameters,the total χ^(2) between the calculations and experimental data was reduced by nearly an order of magnitude.Furthermore,the role of nuclear deformation in the Giant Dipole Resonance(GDR)structure was analyzed,highlighting its impact on the emergence of double peaks in the photon absorption cross sections of deformed nuclei.This work provides a robust microscopic approach to improve photonuclear data for applications in nuclear physics and astrophysics.展开更多
Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized t...Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.展开更多
Defect levels in semiconductor band gaps play a crucial role in functionalized semiconductors for practical applications in optoelectronics;however,first-principle defect calculations based on exchange-correlation fun...Defect levels in semiconductor band gaps play a crucial role in functionalized semiconductors for practical applications in optoelectronics;however,first-principle defect calculations based on exchange-correlation functionals,such as local density approximation,grand gradient approximation(GGA),and hybrid functionals,either underestimate band gaps or misplace defect levels.In this study,we revisited iodine defects in CH_(3)NH_(3)PbI_(3) by combining the accuracy of total energy calculations of GGA and single-electron level calculation of the GW method.The combined approach predicted neutral Im_(i) to be unstable and the transition level of Im_(i)(+1/-1)to be close to the valence band maximum.Therefore,Im_(i) may not be as detrimental as previously reported.Moreover,Vm I may be unstable in the-1 charged state but could still be detrimental owing to the deep transition level of Vm I(+1/0).These results could facilitate the further understanding of the intrinsic point defect and defect passivation observed in CH_(3)NH_(3)PbI_(3).展开更多
The quasiparticle interference(QPI)patterns of the superconducting state in Sr2RuO4 are theoretically studied by taking into account the spin–orbital coupling and two different pairing modes,chiral p-wave pairing and...The quasiparticle interference(QPI)patterns of the superconducting state in Sr2RuO4 are theoretically studied by taking into account the spin–orbital coupling and two different pairing modes,chiral p-wave pairing and equal d-wave pairing,in order to propose an experimental method to test them.Both of the QPI spectra for the two pairing modes have clearly peaks evolving with energy,and their locations can be determined from the tips of the constant energy contour.But the number,location,and evolution of these peaks with energy are different between the two pairing modes.The different behaviors of the QPI patterns in these two pairing modes may help to resolve whether Sr2RuO4 is a chiral p-wave or d-wave superconductor.展开更多
-The calculation method for the transitional odd-A nuclei is studied.The theo-retical calculation of the energy level structure of <sup>147</sup>pm and <sup>149</sup>EU is performed bycoupling ...-The calculation method for the transitional odd-A nuclei is studied.The theo-retical calculation of the energy level structure of <sup>147</sup>pm and <sup>149</sup>EU is performed bycoupling the 1+3 quasiparticles to the anharmonic vibration of the core.Aparticle-number-conservation treatment is made by means of the projection method.The effects of the particle-number projection,the three-d-boson excitation and residualinteraction on the lower excited states are discussed.展开更多
The quasiparticle resonances are investigated by examining three kinds of quasiparticle spectra, i.e., the density of quasiparticle states, the occupation number density, and the pair number density in the continuum S...The quasiparticle resonances are investigated by examining three kinds of quasiparticle spectra, i.e., the density of quasiparticle states, the occupation number density, and the pair number density in the continuum Skyrme Hartree-Fock-Bogoliubov theory with the Green’s function method. Taking the weakly bound nucleus 66Ca as an example, the quasiparticle resonant energies and widths extracted from these three kinds of quasiparticle spectra are compared. For the narrow resonances, the extracted resonant energy and the width are consistent with each other. However, it is difficult to use the density of quasiparticle states to identify the broad resonances due to the background of nonresonant continuum. By switching off the pairing potential and/or the Hartree-Fock(HF) potential respectively in the calculation of these quasiparticle spectra, the roles of HF mean-field and pairing correlations in the quasiparticle resonances are demonstrated clearly. It turns out that all the quasiparticle resonances corresponding to the deeply bound, weakly bound and positive-energy single-particle resonant states, are mainly contributed by the HF potential. The pairing potential helps to slightly increase the resonant energy and the width. However, the pairing potential is important to make the nucleons occupy the low-lying nonresonant continuum states near the threshold and take part in the pairing correlations here,especially for the partial waves with small angular momentum ?.展开更多
We report the ultrafast optical pump-probe spectroscopy measurements on the single-crystal cerium films.Our experimental results of temperature-dependent quasiparticle dynamics reveal development of the hybridization ...We report the ultrafast optical pump-probe spectroscopy measurements on the single-crystal cerium films.Our experimental results of temperature-dependent quasiparticle dynamics reveal development of the hybridization between localized f moments and conduction electrons,i.e.,evolving from fluctuating hybridization to collective hybridization.Exotic phonon renormalization is discovered to appear at the emerging temperature(T^(+))of fluctuating hybridization apart from its known presence at the coherent temperature(T^(*)),and can hardly be explained by the mean-field theory.The quasiparticle relaxation at high temperatures indicates coexistence of nonthermal electron-electron scattering and inelastic Kondo scattering,while its behavior at low temperatures suggests onset ofαphase in theγ-phase dominated film.We also extract the indirect gap below T^(*),representing the appearance of collective hybridization.Our findings provide novel information about the hybridization and phase evolution in the heavy fermion systems.展开更多
The running of the QCD coupling in the effective mass causes thermodynamic inconsistency problem in the conventional quasiparticle model. We provide a novel treatment which removes the inconsistency by an effective ba...The running of the QCD coupling in the effective mass causes thermodynamic inconsistency problem in the conventional quasiparticle model. We provide a novel treatment which removes the inconsistency by an effective bag constant. The chemical potential dependence of the renormalization subtraction point is constrained by the Cauchy condition in the chemical potential space. The stability and microscopic properties of strange quark matter are then studied within the completely self-consistent quasiparticle model, and the obtained equation of state of quark matter is applied to the investigation of strange stars. It is found that our improved model can describe well compact stars with mass about two times the solar mass, which indicates that such massive compact stars could be strange stars.展开更多
Opto-electronics is rooted in the effects and principles of light,photons,and even photonic quasiparticles interaction with matter such as electronics systems,focusing on the generation,transmission,detection,and mani...Opto-electronics is rooted in the effects and principles of light,photons,and even photonic quasiparticles interaction with matter such as electronics systems,focusing on the generation,transmission,detection,and manipulation of energy and information.This field drives innovation across diverse technological domains,including advanced materials,devices,methods,instruments,and equipment that empower humanity to overcome significant challenges in observation,communication,computing,data storage,display technologies,and sustainable energy solutions.展开更多
The continuum quasiparticle random phase approximation(CQRPA),which includes the Skyrme interaction for both groundand excited-state calculations,is extended in a more consistent manner in the present work.The emergen...The continuum quasiparticle random phase approximation(CQRPA),which includes the Skyrme interaction for both groundand excited-state calculations,is extended in a more consistent manner in the present work.The emergence,evolution,and origin of pygmy monopole strengths along the even-even Ni isotopes were investigated carefully within consistent Skyrme HF+BCS and CQRPA models.The SLy5 Skyrme interaction and density-dependent zero-range pairing interactions were adopted in the calculations.No pygmy monopole strength was observed in^(70-78)Ni.However,pronounced pygmy monopole strengths are clearly observed in^(80-84)Ni,which are attributed mainly to the neutron excitations from weakly bound orbitals into the continuum.The neutron states involved in the pygmy monopole strength include 1 g_(9∕2),2 d_(5∕2),3 s_(1∕2)and 2 d_(3∕2).We suggest that more efforts from experimental investigations of pygmy monopole resonance should be made to confirm or disprove the predictions from models in the future.展开更多
The tunneling conductance of two kinds of tunnel junctions with time-reversal symmetry breaking,normal metal/insulator/ferromagnetic metal/dx_(2-y2)+is-wave superconductor(NM/I/FM/dx_(2-y2)+is-wave SC)and NM/I/FM/dx_(...The tunneling conductance of two kinds of tunnel junctions with time-reversal symmetry breaking,normal metal/insulator/ferromagnetic metal/dx_(2-y2)+is-wave superconductor(NM/I/FM/dx_(2-y2)+is-wave SC)and NM/I/FM/dx_(2-y2)+idxy-wave SC,is calculated using the extended Blonder-Tinkham-Klapwijk theoretical method.The ratio of the subdominant s-wave and dxy-wave components to the dominant dx_(2-y2)-wave component is expressed byΔ_(s)/Δ_(D)andΔ_(d)/Δ_(D),respectively.Results show that for NM/I/FM/dx_(2-y2)+is-wave SC tunnel junctions,the splitting of the zero-bias conductance peak(ZBCP)is obtained and the splitting peaks appear at eV/Δ_(0)=±Δ_(s)/Δ_(D)with eV the applied bias voltage andΔ_(0)the zero temperature energy gap of SC.For NM/I/FM/dx_(2-y2)+idxy-wave SC tunnel junctions,there are also conductance peaks at eV/Δ_(0)=±Δ_(d)/Δ_(D)but the ZBCP does not split.For the two types of tunnel junctions,the completely reversed tunnel conductance spectrum indicates that when the exchange energy in FM is increased to a certain value,the proximity effect transforms the tunnel junctions from the'0 state'to the'πstate'.The shortening of the transport quasiparticle lifetime can weaken the proximity effect to smooth out the dips and peaks in the tunnel spectrum.This is considered a possible reason that the ZBCP splitting was not observed in some previous experiments.It is expected that these analysis results can serve as a guide for future experiments and the relevant conclusions can be confirmed.展开更多
Phonon quasiparticles and their anharmonic interactions govern heat transport in insulators.Accurate characterization of phonon frequencies and linewidths,especially beyond the quasiparticle approximation,is essential...Phonon quasiparticles and their anharmonic interactions govern heat transport in insulators.Accurate characterization of phonon frequencies and linewidths,especially beyond the quasiparticle approximation,is essential for understanding anharmonic effects and lattice thermal conductivity.Here,we investigate the anharmonic lattice dynamics and phonon transport in crystalline copper halides CuBiI4 using the self-consistent phonon theory,combined with the Wigner transport formalism and the quasi-harmonic Green–Kubo method.Results show that the three-phonon bubble self-energy substantially renormalizes the phonon dispersion,inducing strong modedependent broadening.Depending on the strength of the anharmonic scattering,phonons exhibit particle-like,wave-like,or overdamped transport characteristics,with broadened states contributing additional coherent thermal transport channels.We establish a consistent description of the overdamped phonon self-energy and advance the microscopic understanding of the strongly anharmonic phonon thermal transport in CuBiI4.Overdamped phonon modes significantly hinder the lattice thermal transport by reducing phonon lifetimes.However,the still well-defined phonon dispersions mitigate carrier scattering induced by the local structural disorder.Anisotropic electrical transport properties are obtained by considering polar and non-polar electroacoustic coupling and ionized impurity scattering mechanisms.Upon electron doping,the thermoelectric figure of merit of n-type CuBiI4 reaches 2.25 at 800 K.展开更多
Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is achieved.The total level density is calculated ...Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is achieved.The total level density is calculated via the convolution of the intrinsic level density and the collective level density.The intrinsic level densities are obtained in the finite-temperature covariant density functional theory,which takes into account the nuclear deformation and pairing self-consistently.For saddle points on the free energy surface in the(β_(2),γ)plane,the entropy and the associated intrinsic level density are compared with those of the global minima.By introducing a quasiparticle to the two neighboring even–even core nuclei,whose properties are determined by the five-dimensional collective Hamiltonian model,the collective levels of the odd-A nuclei are obtained via the CQC model.The total level densities of the^(234-240)U agree well with the available experimental data and Hilaire’s result.Furthermore,the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately.展开更多
Dynamics of domain walls(DWs) was studied in transparent thin orthoferrite samples with weak ferromagnetic ordering at subsonic and supersonic speeds.Direct measurements were made of flexural vibration amplitude in th...Dynamics of domain walls(DWs) was studied in transparent thin orthoferrite samples with weak ferromagnetic ordering at subsonic and supersonic speeds.Direct measurements were made of flexural vibration amplitude in the samples studied,which were induced by a solitary DW with periodic actions of a driving magnetic field.The values of the amplitude reached 7 nm at a resonance.The formation of magnetoelastic solitons was observed and their dynamics was studied at a resonance between an elastic and a spin subsystems.Solitons lag behind the DW at the moment when the DW surpasses the sound barrier and are ahead of it at the subsonic motion.展开更多
Recent years,huge progress of first-principles methods has been witnessed in calculating the quasiparticle band gaps,with many-body perturbation theory in the GW approximation being the standard choice,where G refers ...Recent years,huge progress of first-principles methods has been witnessed in calculating the quasiparticle band gaps,with many-body perturbation theory in the GW approximation being the standard choice,where G refers to Green’s function and W denotes the dynamically screened Coulomb interaction.Numerically,the completeness of the basis set has been extensively discussed,but in practice far from carefully addressed.Beyond the static description of the nuclei,the electron–phonon interactions(EPIs)are ubiquitous,which cause zero-point renormalization(ZPR)of the band gaps.Therefore,to obtain high quality band gaps,one needs both accurate quasiparticle energies and accurate treatments of EPIs.In this article,we review methods on this.The completeness of the basis set is analyzed in the framework of linearized augmented plane waves,by adding high-energy local orbitals(HLOs).The electron–phonon matrix elements and self-energy are discussed,followed by the temperature dependence of the band gaps in both perturbative and non-perturbative methods.Applications of such an analysis on bulk wurtzite BeO and monolayer honeycomb BeO are given.Adding HLOs widens their GW_(0) band gaps by∼0.4 eV while ZPR narrows them by similar amount.These influences cancel each other,which explains the fortuitous agreement between experiment and theory when the basis set is incomplete and the EPIs are absent.The phonon-induced renormalization,a term often neglected in calculations of the band gaps,is also emphasized by its large magnitude.展开更多
We study the behaviors of three-dimensional double and triple Weyl fermions in the presence of weak random potential.By performing the Wilsonian renormalization group(RG)analysis,we reveal that the quasiparticle exper...We study the behaviors of three-dimensional double and triple Weyl fermions in the presence of weak random potential.By performing the Wilsonian renormalization group(RG)analysis,we reveal that the quasiparticle experiences strong renormalization which leads to the modification of the density of states and quasiparticle residue.We further utilize the RG analysis to calculate the classical conductivity and show that the diffusive transport is substantially corrected due to the novel behavior of the quasiparticle and can be directly measured by experiments.展开更多
Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transiti...Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.展开更多
Specific heat is a powerful tool to investigate the physical properties of condensed materials.Superconducting state is achieved through the condensation of paired electrons,namely,the Cooper pairs.The condensed Coope...Specific heat is a powerful tool to investigate the physical properties of condensed materials.Superconducting state is achieved through the condensation of paired electrons,namely,the Cooper pairs.The condensed Cooper pairs have lower entropy compared with that of electrons in normal metal,thus specific heat is very useful in detecting the low lying quasiparticle excitations of the superconducting condensate and the pairing symmetry of the superconducting gap.In this brief overview,we will give an introduction to the specific heat investigation of the physical properties of superconductors.We show the data obtained in cuprate and iron based superconductors to reveal the pairing symmetry of the order parameter.展开更多
基金supported by the National Key Research and Development(R&D)Program(Nos.2022YFA1602403,2021YFA1601500)Key Program of the National Natural Science Foundation of China(No.12435007)+3 种基金the National Natural Science Foundation of China(Nos.12075104,12447106,and 12147101)the Basic Research Project of China National Nuclear Corporation(CNNC)(No.CNDC-JCYJ-202402)CNNC Youth Innovation Team Project Key Laboratory Fund,the Key Laboratory Fund Key Projects(No.JCKY2023201C153-5)Continuous Support Basic Scientific Research Project(BJ010261223282).
文摘In this study,we calculated the photon absorption cross sections of even–even neodymium(Nd)isotopes using the Dirac Quasiparticle Finite Amplitude Method(relativistic QFAM),combined with the Tiny Smearing Approximation(TSA)method.This approach enables the efficient reproduction of experimental photon absorption data for both spherical and deformed nuclei.We demonstrate that relativistic QFAM calculations with any smearing parameter γ can be scaled using the TSA method,significantly reducing the computational cost.Our method was applied to Nd isotopes,with experimental data reproduced for ^(142,144,146,148,150)Nd and predictions for ^(152)Nd.By optimizing the three key parameters,the total χ^(2) between the calculations and experimental data was reduced by nearly an order of magnitude.Furthermore,the role of nuclear deformation in the Giant Dipole Resonance(GDR)structure was analyzed,highlighting its impact on the emergence of double peaks in the photon absorption cross sections of deformed nuclei.This work provides a robust microscopic approach to improve photonuclear data for applications in nuclear physics and astrophysics.
基金Project supported by Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515011227)the National Natural Science Foundation of China(Grant No.51902353)+1 种基金the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.22lgqb03)the Fund from the State Key Laboratory of Optoelectronic Materials and Technologies(Grant No.OEMT-2022-ZRC-01)
文摘Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11974257)the Distinguished Young Talent Funding of Jiangsu Province, China (Grant No. BK20200003)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Defect levels in semiconductor band gaps play a crucial role in functionalized semiconductors for practical applications in optoelectronics;however,first-principle defect calculations based on exchange-correlation functionals,such as local density approximation,grand gradient approximation(GGA),and hybrid functionals,either underestimate band gaps or misplace defect levels.In this study,we revisited iodine defects in CH_(3)NH_(3)PbI_(3) by combining the accuracy of total energy calculations of GGA and single-electron level calculation of the GW method.The combined approach predicted neutral Im_(i) to be unstable and the transition level of Im_(i)(+1/-1)to be close to the valence band maximum.Therefore,Im_(i) may not be as detrimental as previously reported.Moreover,Vm I may be unstable in the-1 charged state but could still be detrimental owing to the deep transition level of Vm I(+1/0).These results could facilitate the further understanding of the intrinsic point defect and defect passivation observed in CH_(3)NH_(3)PbI_(3).
基金National Natural Science Foundataion of China(Grant Nos.11604168,11604166,and 11604303)WSW also acknowledges the supports by K.C.Wong Magna Fund in Ningbo University.
文摘The quasiparticle interference(QPI)patterns of the superconducting state in Sr2RuO4 are theoretically studied by taking into account the spin–orbital coupling and two different pairing modes,chiral p-wave pairing and equal d-wave pairing,in order to propose an experimental method to test them.Both of the QPI spectra for the two pairing modes have clearly peaks evolving with energy,and their locations can be determined from the tips of the constant energy contour.But the number,location,and evolution of these peaks with energy are different between the two pairing modes.The different behaviors of the QPI patterns in these two pairing modes may help to resolve whether Sr2RuO4 is a chiral p-wave or d-wave superconductor.
基金The project supported in part by National Natural Science Foundation of China and by the Grant LWTZ 1298 of Academia Sinica.
文摘-The calculation method for the transitional odd-A nuclei is studied.The theo-retical calculation of the energy level structure of <sup>147</sup>pm and <sup>149</sup>EU is performed bycoupling the 1+3 quasiparticles to the anharmonic vibration of the core.Aparticle-number-conservation treatment is made by means of the projection method.The effects of the particle-number projection,the three-d-boson excitation and residualinteraction on the lower excited states are discussed.
基金supported by the National Key R&D Program of China(Grant No.2018YFA0404400)the National Natural Science Foundation of China(Grant Nos.11621131001,11405116,and 11875075)
文摘The quasiparticle resonances are investigated by examining three kinds of quasiparticle spectra, i.e., the density of quasiparticle states, the occupation number density, and the pair number density in the continuum Skyrme Hartree-Fock-Bogoliubov theory with the Green’s function method. Taking the weakly bound nucleus 66Ca as an example, the quasiparticle resonant energies and widths extracted from these three kinds of quasiparticle spectra are compared. For the narrow resonances, the extracted resonant energy and the width are consistent with each other. However, it is difficult to use the density of quasiparticle states to identify the broad resonances due to the background of nonresonant continuum. By switching off the pairing potential and/or the Hartree-Fock(HF) potential respectively in the calculation of these quasiparticle spectra, the roles of HF mean-field and pairing correlations in the quasiparticle resonances are demonstrated clearly. It turns out that all the quasiparticle resonances corresponding to the deeply bound, weakly bound and positive-energy single-particle resonant states, are mainly contributed by the HF potential. The pairing potential helps to slightly increase the resonant energy and the width. However, the pairing potential is important to make the nucleons occupy the low-lying nonresonant continuum states near the threshold and take part in the pairing correlations here,especially for the partial waves with small angular momentum ?.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403000,and 2022YFA1402200)the National Natural Science Foundation of China(Grant Nos.92365102,11974070,11734006,11925408,11921004,12004067,62027807,and 12174331)the Frontier Science Project of Dongguan(Grant No.2019622101004)。
文摘We report the ultrafast optical pump-probe spectroscopy measurements on the single-crystal cerium films.Our experimental results of temperature-dependent quasiparticle dynamics reveal development of the hybridization between localized f moments and conduction electrons,i.e.,evolving from fluctuating hybridization to collective hybridization.Exotic phonon renormalization is discovered to appear at the emerging temperature(T^(+))of fluctuating hybridization apart from its known presence at the coherent temperature(T^(*)),and can hardly be explained by the mean-field theory.The quasiparticle relaxation at high temperatures indicates coexistence of nonthermal electron-electron scattering and inelastic Kondo scattering,while its behavior at low temperatures suggests onset ofαphase in theγ-phase dominated film.We also extract the indirect gap below T^(*),representing the appearance of collective hybridization.Our findings provide novel information about the hybridization and phase evolution in the heavy fermion systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.11135011,11475110 and 11575190)
文摘The running of the QCD coupling in the effective mass causes thermodynamic inconsistency problem in the conventional quasiparticle model. We provide a novel treatment which removes the inconsistency by an effective bag constant. The chemical potential dependence of the renormalization subtraction point is constrained by the Cauchy condition in the chemical potential space. The stability and microscopic properties of strange quark matter are then studied within the completely self-consistent quasiparticle model, and the obtained equation of state of quark matter is applied to the investigation of strange stars. It is found that our improved model can describe well compact stars with mass about two times the solar mass, which indicates that such massive compact stars could be strange stars.
文摘Opto-electronics is rooted in the effects and principles of light,photons,and even photonic quasiparticles interaction with matter such as electronics systems,focusing on the generation,transmission,detection,and manipulation of energy and information.This field drives innovation across diverse technological domains,including advanced materials,devices,methods,instruments,and equipment that empower humanity to overcome significant challenges in observation,communication,computing,data storage,display technologies,and sustainable energy solutions.
基金partly supported by the National Natural Science Foundation of China(Nos.12275025,11975096,12135004,and 11961141004)the Fundamental Research Funds for the Central Universities(No.2020NTST06)。
文摘The continuum quasiparticle random phase approximation(CQRPA),which includes the Skyrme interaction for both groundand excited-state calculations,is extended in a more consistent manner in the present work.The emergence,evolution,and origin of pygmy monopole strengths along the even-even Ni isotopes were investigated carefully within consistent Skyrme HF+BCS and CQRPA models.The SLy5 Skyrme interaction and density-dependent zero-range pairing interactions were adopted in the calculations.No pygmy monopole strength was observed in^(70-78)Ni.However,pronounced pygmy monopole strengths are clearly observed in^(80-84)Ni,which are attributed mainly to the neutron excitations from weakly bound orbitals into the continuum.The neutron states involved in the pygmy monopole strength include 1 g_(9∕2),2 d_(5∕2),3 s_(1∕2)and 2 d_(3∕2).We suggest that more efforts from experimental investigations of pygmy monopole resonance should be made to confirm or disprove the predictions from models in the future.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.23CX03016A and 24CX030009A)。
文摘The tunneling conductance of two kinds of tunnel junctions with time-reversal symmetry breaking,normal metal/insulator/ferromagnetic metal/dx_(2-y2)+is-wave superconductor(NM/I/FM/dx_(2-y2)+is-wave SC)and NM/I/FM/dx_(2-y2)+idxy-wave SC,is calculated using the extended Blonder-Tinkham-Klapwijk theoretical method.The ratio of the subdominant s-wave and dxy-wave components to the dominant dx_(2-y2)-wave component is expressed byΔ_(s)/Δ_(D)andΔ_(d)/Δ_(D),respectively.Results show that for NM/I/FM/dx_(2-y2)+is-wave SC tunnel junctions,the splitting of the zero-bias conductance peak(ZBCP)is obtained and the splitting peaks appear at eV/Δ_(0)=±Δ_(s)/Δ_(D)with eV the applied bias voltage andΔ_(0)the zero temperature energy gap of SC.For NM/I/FM/dx_(2-y2)+idxy-wave SC tunnel junctions,there are also conductance peaks at eV/Δ_(0)=±Δ_(d)/Δ_(D)but the ZBCP does not split.For the two types of tunnel junctions,the completely reversed tunnel conductance spectrum indicates that when the exchange energy in FM is increased to a certain value,the proximity effect transforms the tunnel junctions from the'0 state'to the'πstate'.The shortening of the transport quasiparticle lifetime can weaken the proximity effect to smooth out the dips and peaks in the tunnel spectrum.This is considered a possible reason that the ZBCP splitting was not observed in some previous experiments.It is expected that these analysis results can serve as a guide for future experiments and the relevant conclusions can be confirmed.
基金supported by the National Natural Science Foundation of China(Grant Nos.12574028,U2330104,and 12074381)Guang-dong Basic and Applied Basic Research Foundation(Grant No.2024A1515010484)。
文摘Phonon quasiparticles and their anharmonic interactions govern heat transport in insulators.Accurate characterization of phonon frequencies and linewidths,especially beyond the quasiparticle approximation,is essential for understanding anharmonic effects and lattice thermal conductivity.Here,we investigate the anharmonic lattice dynamics and phonon transport in crystalline copper halides CuBiI4 using the self-consistent phonon theory,combined with the Wigner transport formalism and the quasi-harmonic Green–Kubo method.Results show that the three-phonon bubble self-energy substantially renormalizes the phonon dispersion,inducing strong modedependent broadening.Depending on the strength of the anharmonic scattering,phonons exhibit particle-like,wave-like,or overdamped transport characteristics,with broadened states contributing additional coherent thermal transport channels.We establish a consistent description of the overdamped phonon self-energy and advance the microscopic understanding of the strongly anharmonic phonon thermal transport in CuBiI4.Overdamped phonon modes significantly hinder the lattice thermal transport by reducing phonon lifetimes.However,the still well-defined phonon dispersions mitigate carrier scattering induced by the local structural disorder.Anisotropic electrical transport properties are obtained by considering polar and non-polar electroacoustic coupling and ionized impurity scattering mechanisms.Upon electron doping,the thermoelectric figure of merit of n-type CuBiI4 reaches 2.25 at 800 K.
基金supported by the China Institute of Atomic Energy(No.401Y-FW-GKXJ-21-1496)the Natural Science Foundation of Henan Province(No.202300410480 and 202300410479)+1 种基金the Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(No.NLK2021-01)the National Natural Science Foundation of China(No.U2032141).
文摘Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is achieved.The total level density is calculated via the convolution of the intrinsic level density and the collective level density.The intrinsic level densities are obtained in the finite-temperature covariant density functional theory,which takes into account the nuclear deformation and pairing self-consistently.For saddle points on the free energy surface in the(β_(2),γ)plane,the entropy and the associated intrinsic level density are compared with those of the global minima.By introducing a quasiparticle to the two neighboring even–even core nuclei,whose properties are determined by the five-dimensional collective Hamiltonian model,the collective levels of the odd-A nuclei are obtained via the CQC model.The total level densities of the^(234-240)U agree well with the available experimental data and Hilaire’s result.Furthermore,the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately.
文摘Dynamics of domain walls(DWs) was studied in transparent thin orthoferrite samples with weak ferromagnetic ordering at subsonic and supersonic speeds.Direct measurements were made of flexural vibration amplitude in the samples studied,which were induced by a solitary DW with periodic actions of a driving magnetic field.The values of the amplitude reached 7 nm at a resonance.The formation of magnetoelastic solitons was observed and their dynamics was studied at a resonance between an elastic and a spin subsystems.Solitons lag behind the DW at the moment when the DW surpasses the sound barrier and are ahead of it at the subsonic motion.
基金Project supported by the National Key Research and Development Program of China (Grand Nos. 2016YFA0300900 and 2017YFA0205003)the National Natual Science Foundation of China (Grant Nos. 11934003, 11774003, and 11634001)+3 种基金the Beijing Natural Science FoundationChina (Grant No. Z200004)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB33010400)supported by the High-performance Computing Platform of Peking University,China
文摘Recent years,huge progress of first-principles methods has been witnessed in calculating the quasiparticle band gaps,with many-body perturbation theory in the GW approximation being the standard choice,where G refers to Green’s function and W denotes the dynamically screened Coulomb interaction.Numerically,the completeness of the basis set has been extensively discussed,but in practice far from carefully addressed.Beyond the static description of the nuclei,the electron–phonon interactions(EPIs)are ubiquitous,which cause zero-point renormalization(ZPR)of the band gaps.Therefore,to obtain high quality band gaps,one needs both accurate quasiparticle energies and accurate treatments of EPIs.In this article,we review methods on this.The completeness of the basis set is analyzed in the framework of linearized augmented plane waves,by adding high-energy local orbitals(HLOs).The electron–phonon matrix elements and self-energy are discussed,followed by the temperature dependence of the band gaps in both perturbative and non-perturbative methods.Applications of such an analysis on bulk wurtzite BeO and monolayer honeycomb BeO are given.Adding HLOs widens their GW_(0) band gaps by∼0.4 eV while ZPR narrows them by similar amount.These influences cancel each other,which explains the fortuitous agreement between experiment and theory when the basis set is incomplete and the EPIs are absent.The phonon-induced renormalization,a term often neglected in calculations of the band gaps,is also emphasized by its large magnitude.
基金Project supported by the National Natural Science Foundation of China(Grant No.11874337).
文摘We study the behaviors of three-dimensional double and triple Weyl fermions in the presence of weak random potential.By performing the Wilsonian renormalization group(RG)analysis,we reveal that the quasiparticle experiences strong renormalization which leads to the modification of the density of states and quasiparticle residue.We further utilize the RG analysis to calculate the classical conductivity and show that the diffusive transport is substantially corrected due to the novel behavior of the quasiparticle and can be directly measured by experiments.
基金Project supported by the Scientific Research Foundation for Youth Academic Talent of Inner Mongolia University (Grant No.1000023112101/010)the Fundamental Research Funds for the Central Universities of China (Grant No.JN200208)+2 种基金supported by the National Natural Science Foundation of China (Grant No.11474023)supported by the National Key Research and Development Program of China (Grant No.2021YFA1401803)the National Natural Science Foundation of China (Grant Nos.11974051 and 11734002)。
文摘Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.
文摘Specific heat is a powerful tool to investigate the physical properties of condensed materials.Superconducting state is achieved through the condensation of paired electrons,namely,the Cooper pairs.The condensed Cooper pairs have lower entropy compared with that of electrons in normal metal,thus specific heat is very useful in detecting the low lying quasiparticle excitations of the superconducting condensate and the pairing symmetry of the superconducting gap.In this brief overview,we will give an introduction to the specific heat investigation of the physical properties of superconductors.We show the data obtained in cuprate and iron based superconductors to reveal the pairing symmetry of the order parameter.
