Nordihydroguaiaretic acid (NDGA) has been synthesized in nine steps from piperonal using Stobbe condensation as the key step with high yield. By this approach, five relative natural products were obtained.
Clinical application of bare metal stents is constrained by the occurrence of instent restenosis,mainly due to the complex biomechanical environment in the body.Numerical simulation method was used to evaluate the eff...Clinical application of bare metal stents is constrained by the occurrence of instent restenosis,mainly due to the complex biomechanical environment in the body.Numerical simulation method was used to evaluate the effect of plaque composition on stent performance in a carotid artery.CT angiography(CTA)data were used as a reference,and zero-load state of the carotid artery was used to establish a 3D stenotic artery model.Different plaque compositions,calcified and hypo-cellular were defined in Model 1 and Model 2,respectively.Interactions between the stents and arterial tissues within the stent crimping-expansion process were analyzed to explore the effects of plaque composition on the mechanical parameters of carotid stents.Goodman diagram and fatigue safety factor(FSF)were analyzed to explore the effects of plaque composition on fatigue performance of a carotid stent in the stent service process.In the stent crimping-expansion process,the von Mises stress in the stent and the dog-boning ratio in Model 1 were higher than that in Model 2.The calcified plaque prevented the stent from expanding the stenotic vessel to a pre-set diameter.Thus,the risk of rupture in the calcified plaque was higher than that in the hypo-cellular plaque.Plaque also affected the stress/strain in the vessel wall,which was observed to be lower in Model 1 than in Model 2.This indicated that calcified plaque could decrease the stress-induced injury of arterial tissues.Within the stent service process,the stents used in these two models were predicted to not fail under fatigue rupture as calculated by the Goodman diagram.Additionally,the points closer to the fatigue limit were generally observed at the inner bend of the stent crowns.The FSF of the stent in Model 1 was lower than that in Model 2.The stent operating in the presence of calcified plaques suffered high risk of fractures.Reliability and fatigue performance of the stent were found to be associated with plaque composition.Hence,this study may provide stent designers an approach toward enhancing the mechanical reliability of a stent.展开更多
Biodegradable zinc alloy stents are a prospective solution for complications caused by the incompatibility between artery and permanent stents.However,insufficient scaffolding has limited the clinical application of b...Biodegradable zinc alloy stents are a prospective solution for complications caused by the incompatibility between artery and permanent stents.However,insufficient scaffolding has limited the clinical application of biodegradable zinc alloy stents.Therefore,in this study,a new stent concept was designed to improve the scaffolding.The mechanical performances of the new and a traditional design stent were investigated and compared using finite element analysis(FEA).The new and traditional design stent were expanded to the intended radial displacement of 0.24 mm under the expansion pressure of 0.58 MPa and 0.45 MPa,respectively.Then,a pressure load of 0.35 MPa was exerted on the outer surfaces of the two stents to compress them.The results showed that the radial recoiling ratio were 45.3%and 83.3%for the new and the traditional stent,respectively.The simulations demonstrate that the biodegradable zinc alloy stent offers enhanced support because of the new structural design.This study implies that biodegradable zinc alloy stent can be a new competitive intervention device for the future clinical cardiovascular application.展开更多
We theoretically explore the tunability of magnomechanically induced transparency(MMIT) phenomenon and fastslow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet(YIG) s...We theoretically explore the tunability of magnomechanically induced transparency(MMIT) phenomenon and fastslow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet(YIG) sphere and an atomic ensemble are placed inside a microwave cavity. In the probe output spectrum, we can observe magnoninduced transparency(MIT) and MMIT due to the photon-magnon and phonon-magnon couplings. We further investigate the effect of atomic ensemble on the absorption spectrum. The results show that better transparency can be obtained by choosing appropriate atomic ensemble parameters. We give an explicit explanation for the mechanism of the Fano resonance phenomenon. Moreover, we discuss phenomena of slow-light propagation. The maximum group delay increases significantly with the increasing atom–cavity coupling strength, and the conversion between slow light and fast light can also be achieved by adjusting the atom–cavity coupling strength. These results may have potential applications for quantum information processing and high precision measurements.展开更多
The {111} fiND plane texture, grain boundary characterization and grain boundary segregation of phos- phorus are investigated for the phosphorus added high strength interstitial free （IF） steel annealed at 810℃ for...The {111} fiND plane texture, grain boundary characterization and grain boundary segregation of phos- phorus are investigated for the phosphorus added high strength interstitial free （IF） steel annealed at 810℃ for 60 s to 180 s. The results show that the maximum volume fraction of {111} fiND plane texture is about 85% and the grain boundary Segregation peak of phosphorus is about 14 at. % for the steel annealed at 810℃ for 120 s. The ∑3 and other low-∑CSL （coincident site lattice） boundaries are lowest for the steel annealed for 120 s. Segregation of phosphorus is also found at low angle grain boundaries.展开更多
To study the diverse coordination modes of the H_2btib,three new coordination architectures,namely, [Ag（Hbtib）CH_3CN]_n（1）,）[Ag（Hbtib）]_n（2） and[Pb（btib）（CH_3OH）_2]_n（3）（where H_2btib=4-（（2-butyl-5-...To study the diverse coordination modes of the H_2btib,three new coordination architectures,namely, [Ag（Hbtib）CH_3CN]_n（1）,）[Ag（Hbtib）]_n（2） and[Pb（btib）（CH_3OH）_2]_n（3）（where H_2btib=4-（（2-butyl-5-（2- carboxy-3-（thiophen-2-yl）prop-1-enyl）-1H-imidazol-1-yl）methyl）benzoic acid） have been synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.Complex 1 exhibits 1D single chain structure,while 2 shows 1D double metal chain motif,and 3 features a 2D layer topology.Also,1,2 and 3 display strong emission band in the solid state at room temperature.展开更多
Therapeutic cancer vaccines aim to expand and activate antigen-specific T cells for the targeted elimination of cancer cells.While early clinical trials faced challenges due to suboptimal antigen-specific T-cell activ...Therapeutic cancer vaccines aim to expand and activate antigen-specific T cells for the targeted elimination of cancer cells.While early clinical trials faced challenges due to suboptimal antigen-specific T-cell activation,recent advancements in antigen discovery and vaccine platform engineering have revitalized the field.This review provides a comprehensive overview of key tumor antigens,including tumor-associated antigens,viral oncoprotein antigens,neoantigens,and cryptic antigens,with a focus on their immunogenicity and therapeutic potential.Advances in our understanding of traditional cancer vaccination targets,in conjunction with the timely identification of novel antigen epitopes,have facilitated the strategic selection of vaccination targets.We also discuss the evolution of cancer vaccine platforms—spanning peptide-based formulations to advanced mRNA vectors—emphasizing innovative strategies to optimize antigen delivery efficiency and adjuvant effects.Efficient antigen delivery and adjuvant selection overcome immune tolerance and tumor-induced immunosuppression.Furthermore,we examine recent clinical trial data and emerging combination approaches that integrate cancer vaccines with other immunotherapies to increase efficacy.While significant progress has been made,challenges remain in improving vaccine-induced T-cell responses,overcoming immune suppression,and translating these advances into effective clinical interventions.Addressing these hurdles will be critical for realizing the full potential of cancer vaccines in immunotherapy.展开更多
Arabinogalactan proteins(AGPs)are widely distributed in plant cells.Fasciclin-like AGPs(FLAs)belong to a subclass of AGPs that play important roles in plant growth and development.However,little is known about the bio...Arabinogalactan proteins(AGPs)are widely distributed in plant cells.Fasciclin-like AGPs(FLAs)belong to a subclass of AGPs that play important roles in plant growth and development.However,little is known about the biological functions of rice FLA.Herein,we report the identification of a male-sterile mutant of DEFECTIVE EXINE AND APERTURE PATTERNING1(DEAP1)in rice.The deap1 mutant anthers produced aberrant pollen grains with defective exine formation and a flattened aperture annulus and exhibited slightly delayed tapetum degradation.DEAP1 encodes a plasma membrane-associated member of groupⅢplant FLAs and is specifically and temporally expressed in reproductive cells and the tapetum layer during male development.Gene expression studies revealed reduced transcript accumulation of genes related to exine formation,aperture patterning,and tapetum development in deap1 mutants.Moreover,DEAP1 may interact with two rice D6 PROTEIN KINASE-LIKE3 s(OsD6PKL3s),homologs of a known Arabidopsis aperture protein,to affect rice pollen aperture development.Our findings suggested that DEAP1 is involved in male reproductive development and may affect exine formation and aperture patterning,thereby providing new insights into the molecular functions of plant FLAs in male fertility.展开更多
Microtubules(MTs)are key players in cell division,migration,and signaling,and they are regarded as important targets for cancer treatment.In this work,two fullerene(C_(60))-functionalized Ir(Ⅲ)complexes(Ir-C_(60)1 an...Microtubules(MTs)are key players in cell division,migration,and signaling,and they are regarded as important targets for cancer treatment.In this work,two fullerene(C_(60))-functionalized Ir(Ⅲ)complexes(Ir-C_(60)1 and Ir-C_(60)2)are rationally designed as dual reactive oxygen species(ROS)regulators and MT-targeted Type Ⅰ/Ⅱ photosensitizers.In the dark,Ir-C_(60)1 and Ir-C_(60)2 serve as ROS scavengers to eliminate O_(2)·^(−)and·OH,consequently reducing the dark cytotoxicity and reversing dysfunctional T cells.Due to the efficiently populated C_(60)-localized intraligand triplet state,Ir-C_(60)1 and Ir-C_(60)2 can be excited by green light(525 nm)to produce O_(2)·^(−)and·OONO−(Type Ⅰ)and ^(1)O_(2)(Type Ⅱ)to overcome tumor hypoxia.Moreover,Ir-C_(60)1 is also able to photooxidize tubulin,consequently interfering with the cellular cytoskeleton structures,inducing immunogenic cell death and inhibiting cell proliferation and migration.Finally,Ir-C_(60)1 exhibits promising photo-immunotherapeutic effects both in vitro and in vivo.In all,we report here the first MT stabilizing photosensitizer performing through Type I/II photodynamic therapy pathways,which provides insights into the rational design of new photo-immunotherapeutic agents targeting specific biomolecules.展开更多
Magnetic impurities in superconductors are of increasing interest due to emergent Yu-Shiba-Rusinov(YSR)states and Majorana zero modes for fault-tolerant quantum computation.However,a direct relationship between the YS...Magnetic impurities in superconductors are of increasing interest due to emergent Yu-Shiba-Rusinov(YSR)states and Majorana zero modes for fault-tolerant quantum computation.However,a direct relationship between the YSR multiple states and magnetic anisotropy splitting of quantum impurity spins remains poorly characterized.By using scanning tunneling microscopy,we systematically resolve individual transition-metal(Fe,Cr,and Ni)impurities induced YSR multiplets as well as their Zeeman effects in the K_(3)C_(60)superconductor.The YSR multiplets show identical d orbital-like wave functions that are symmetry-mismatched to the threefold K_(3)C_(60)(111)host surface,breaking point-group symmetries of the spatial distribution of YSR bound states in real space.Remarkably,we identify an unprecedented fermion-parity-preserving quantum phase transition between ground states with opposite signs of the uniaxial magnetic anisotropy that can be manipulated by an external magnetic field.These findings can be readily understood in terms of anisotropy splitting of quantum impurity spins,and thus elucidate the intricate interplay between the magnetic anisotropy and YSR multiplets.展开更多
The Mn-Bi-Te class of compounds are recently discovered topological insulators with broken time-reversal-symmetry,which host unique quantum anomalous Hall and axion insulator states.Their key characteristics are belie...The Mn-Bi-Te class of compounds are recently discovered topological insulators with broken time-reversal-symmetry,which host unique quantum anomalous Hall and axion insulator states.Their key characteristics are believed to be sufficiently understood by models in a single-particle picture.Here,we apply scanning tunneling microscopy to study the electronic properties of MnBi_(2)Te_(4)and MnBi_(4)Te_(7).Unexpectedly,our quasiparticle interference(QPI)results demonstrate that rotational symmetry of the crystal breaks,i.e.a nematic-like pattern arises,in certain energy range but persists in others.Moreover,our data in the presence of an external magnetic field rule out the possibility of the material magnetism as an origin of the C2 symmetric QPI pattern.This study reveals that the interaction in the Mn-Bi-Te class of topological materials may play an essential role in their electronic states,and thus opens a new path for investigating the interplay between wavefunction topology and symmetry breaking phases.展开更多
基金We are grateful to the National Natural Science Foundation of China (NSFC QT program No.20172023) and Natural Science Foundation of Gansu province (ZS001-A25-003-Z).
文摘Nordihydroguaiaretic acid (NDGA) has been synthesized in nine steps from piperonal using Stobbe condensation as the key step with high yield. By this approach, five relative natural products were obtained.
基金supported by Major Project of Science and Technology of Beijing Municipal Education Commission and Type B Project of Beijing Natural Science Foundation(KZ201710005007).
文摘Clinical application of bare metal stents is constrained by the occurrence of instent restenosis,mainly due to the complex biomechanical environment in the body.Numerical simulation method was used to evaluate the effect of plaque composition on stent performance in a carotid artery.CT angiography(CTA)data were used as a reference,and zero-load state of the carotid artery was used to establish a 3D stenotic artery model.Different plaque compositions,calcified and hypo-cellular were defined in Model 1 and Model 2,respectively.Interactions between the stents and arterial tissues within the stent crimping-expansion process were analyzed to explore the effects of plaque composition on the mechanical parameters of carotid stents.Goodman diagram and fatigue safety factor(FSF)were analyzed to explore the effects of plaque composition on fatigue performance of a carotid stent in the stent service process.In the stent crimping-expansion process,the von Mises stress in the stent and the dog-boning ratio in Model 1 were higher than that in Model 2.The calcified plaque prevented the stent from expanding the stenotic vessel to a pre-set diameter.Thus,the risk of rupture in the calcified plaque was higher than that in the hypo-cellular plaque.Plaque also affected the stress/strain in the vessel wall,which was observed to be lower in Model 1 than in Model 2.This indicated that calcified plaque could decrease the stress-induced injury of arterial tissues.Within the stent service process,the stents used in these two models were predicted to not fail under fatigue rupture as calculated by the Goodman diagram.Additionally,the points closer to the fatigue limit were generally observed at the inner bend of the stent crowns.The FSF of the stent in Model 1 was lower than that in Model 2.The stent operating in the presence of calcified plaques suffered high risk of fractures.Reliability and fatigue performance of the stent were found to be associated with plaque composition.Hence,this study may provide stent designers an approach toward enhancing the mechanical reliability of a stent.
基金Major Project of Science and Technology of Beijing Municipal Education Commission and Type B Project of Beijing Natural Science Foundation(KZ201710005007)Part of the study was performed under the General Collaborative Research Project of the Institute of Fluid Science,Tohoku University(J17I105).
文摘Biodegradable zinc alloy stents are a prospective solution for complications caused by the incompatibility between artery and permanent stents.However,insufficient scaffolding has limited the clinical application of biodegradable zinc alloy stents.Therefore,in this study,a new stent concept was designed to improve the scaffolding.The mechanical performances of the new and a traditional design stent were investigated and compared using finite element analysis(FEA).The new and traditional design stent were expanded to the intended radial displacement of 0.24 mm under the expansion pressure of 0.58 MPa and 0.45 MPa,respectively.Then,a pressure load of 0.35 MPa was exerted on the outer surfaces of the two stents to compress them.The results showed that the radial recoiling ratio were 45.3%and 83.3%for the new and the traditional stent,respectively.The simulations demonstrate that the biodegradable zinc alloy stent offers enhanced support because of the new structural design.This study implies that biodegradable zinc alloy stent can be a new competitive intervention device for the future clinical cardiovascular application.
基金the National Natural Science Foundation of China (Grant No. 62061028)the Opening Project of Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology (Grant No. ammt2021A4)+4 种基金the Foundation for Distinguished Young Scientists of Jiangxi Province (Grant No. 20162BCB23009)the Open Research Fund Program of the State Key Laboratory of LowDimensional Quantum Physics (Grant No. KF202010)the Interdisciplinary Innovation Fund of Nanchang University (Grant No. 9166-27060003-YB12)the Open Research Fund Program of Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education (Grant No. OEIAM202004)the Graduate Innovation Special Fund of Jiangxi Province (Grant No. YC2021-S054)。
文摘We theoretically explore the tunability of magnomechanically induced transparency(MMIT) phenomenon and fastslow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet(YIG) sphere and an atomic ensemble are placed inside a microwave cavity. In the probe output spectrum, we can observe magnoninduced transparency(MIT) and MMIT due to the photon-magnon and phonon-magnon couplings. We further investigate the effect of atomic ensemble on the absorption spectrum. The results show that better transparency can be obtained by choosing appropriate atomic ensemble parameters. We give an explicit explanation for the mechanism of the Fano resonance phenomenon. Moreover, we discuss phenomena of slow-light propagation. The maximum group delay increases significantly with the increasing atom–cavity coupling strength, and the conversion between slow light and fast light can also be achieved by adjusting the atom–cavity coupling strength. These results may have potential applications for quantum information processing and high precision measurements.
基金Item Sponsored by National Natural Science Foundation of China(51101114,50901054)
文摘The {111} fiND plane texture, grain boundary characterization and grain boundary segregation of phos- phorus are investigated for the phosphorus added high strength interstitial free （IF） steel annealed at 810℃ for 60 s to 180 s. The results show that the maximum volume fraction of {111} fiND plane texture is about 85% and the grain boundary Segregation peak of phosphorus is about 14 at. % for the steel annealed at 810℃ for 120 s. The ∑3 and other low-∑CSL （coincident site lattice） boundaries are lowest for the steel annealed for 120 s. Segregation of phosphorus is also found at low angle grain boundaries.
基金the financial support by the He'nan Key Science and Technology Research(Nos.112102310084 and 122102310061)
文摘To study the diverse coordination modes of the H_2btib,three new coordination architectures,namely, [Ag（Hbtib）CH_3CN]_n（1）,）[Ag（Hbtib）]_n（2） and[Pb（btib）（CH_3OH）_2]_n（3）（where H_2btib=4-（（2-butyl-5-（2- carboxy-3-（thiophen-2-yl）prop-1-enyl）-1H-imidazol-1-yl）methyl）benzoic acid） have been synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.Complex 1 exhibits 1D single chain structure,while 2 shows 1D double metal chain motif,and 3 features a 2D layer topology.Also,1,2 and 3 display strong emission band in the solid state at room temperature.
基金supported by funding from the National Science and Technology Major Project of the Ministry of Science and Technology of China(2023YFC2508505)grants from the Natural Science Foundation of China(82250710684).
文摘Therapeutic cancer vaccines aim to expand and activate antigen-specific T cells for the targeted elimination of cancer cells.While early clinical trials faced challenges due to suboptimal antigen-specific T-cell activation,recent advancements in antigen discovery and vaccine platform engineering have revitalized the field.This review provides a comprehensive overview of key tumor antigens,including tumor-associated antigens,viral oncoprotein antigens,neoantigens,and cryptic antigens,with a focus on their immunogenicity and therapeutic potential.Advances in our understanding of traditional cancer vaccination targets,in conjunction with the timely identification of novel antigen epitopes,have facilitated the strategic selection of vaccination targets.We also discuss the evolution of cancer vaccine platforms—spanning peptide-based formulations to advanced mRNA vectors—emphasizing innovative strategies to optimize antigen delivery efficiency and adjuvant effects.Efficient antigen delivery and adjuvant selection overcome immune tolerance and tumor-induced immunosuppression.Furthermore,we examine recent clinical trial data and emerging combination approaches that integrate cancer vaccines with other immunotherapies to increase efficacy.While significant progress has been made,challenges remain in improving vaccine-induced T-cell responses,overcoming immune suppression,and translating these advances into effective clinical interventions.Addressing these hurdles will be critical for realizing the full potential of cancer vaccines in immunotherapy.
基金supported by funds from the National Natural Science Foundation of China(31901482,31971863,31971867 and 32171966)the Open Research Fund of the State Key Laboratory of Hybrid Rice(Hunan Hybrid Rice Research Centre,2016KF10)the Sichuan Province Science and Technology Support Program(2021YFYZ0016,2021YFYZ0027,2020YJ0139)。
文摘Arabinogalactan proteins(AGPs)are widely distributed in plant cells.Fasciclin-like AGPs(FLAs)belong to a subclass of AGPs that play important roles in plant growth and development.However,little is known about the biological functions of rice FLA.Herein,we report the identification of a male-sterile mutant of DEFECTIVE EXINE AND APERTURE PATTERNING1(DEAP1)in rice.The deap1 mutant anthers produced aberrant pollen grains with defective exine formation and a flattened aperture annulus and exhibited slightly delayed tapetum degradation.DEAP1 encodes a plasma membrane-associated member of groupⅢplant FLAs and is specifically and temporally expressed in reproductive cells and the tapetum layer during male development.Gene expression studies revealed reduced transcript accumulation of genes related to exine formation,aperture patterning,and tapetum development in deap1 mutants.Moreover,DEAP1 may interact with two rice D6 PROTEIN KINASE-LIKE3 s(OsD6PKL3s),homologs of a known Arabidopsis aperture protein,to affect rice pollen aperture development.Our findings suggested that DEAP1 is involved in male reproductive development and may affect exine formation and aperture patterning,thereby providing new insights into the molecular functions of plant FLAs in male fertility.
基金National Natural Science Foundation of China,Grant/Award Number:22177142Basic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Numbers:2022A1515111089,2023A1515010625,2024B1515040028。
文摘Microtubules(MTs)are key players in cell division,migration,and signaling,and they are regarded as important targets for cancer treatment.In this work,two fullerene(C_(60))-functionalized Ir(Ⅲ)complexes(Ir-C_(60)1 and Ir-C_(60)2)are rationally designed as dual reactive oxygen species(ROS)regulators and MT-targeted Type Ⅰ/Ⅱ photosensitizers.In the dark,Ir-C_(60)1 and Ir-C_(60)2 serve as ROS scavengers to eliminate O_(2)·^(−)and·OH,consequently reducing the dark cytotoxicity and reversing dysfunctional T cells.Due to the efficiently populated C_(60)-localized intraligand triplet state,Ir-C_(60)1 and Ir-C_(60)2 can be excited by green light(525 nm)to produce O_(2)·^(−)and·OONO−(Type Ⅰ)and ^(1)O_(2)(Type Ⅱ)to overcome tumor hypoxia.Moreover,Ir-C_(60)1 is also able to photooxidize tubulin,consequently interfering with the cellular cytoskeleton structures,inducing immunogenic cell death and inhibiting cell proliferation and migration.Finally,Ir-C_(60)1 exhibits promising photo-immunotherapeutic effects both in vitro and in vivo.In all,we report here the first MT stabilizing photosensitizer performing through Type I/II photodynamic therapy pathways,which provides insights into the rational design of new photo-immunotherapeutic agents targeting specific biomolecules.
基金financially supported by the National Key Research and Development Program of China(2022YFA1403100,2017YFA0304600)the National Natural Science Foundation of China(12141403,52388201)+1 种基金the Suzhou Science and Technology Program(SJC2021009)Nano-X from the Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO),the Chinese Academy of Sciences.
文摘Magnetic impurities in superconductors are of increasing interest due to emergent Yu-Shiba-Rusinov(YSR)states and Majorana zero modes for fault-tolerant quantum computation.However,a direct relationship between the YSR multiple states and magnetic anisotropy splitting of quantum impurity spins remains poorly characterized.By using scanning tunneling microscopy,we systematically resolve individual transition-metal(Fe,Cr,and Ni)impurities induced YSR multiplets as well as their Zeeman effects in the K_(3)C_(60)superconductor.The YSR multiplets show identical d orbital-like wave functions that are symmetry-mismatched to the threefold K_(3)C_(60)(111)host surface,breaking point-group symmetries of the spatial distribution of YSR bound states in real space.Remarkably,we identify an unprecedented fermion-parity-preserving quantum phase transition between ground states with opposite signs of the uniaxial magnetic anisotropy that can be manipulated by an external magnetic field.These findings can be readily understood in terms of anisotropy splitting of quantum impurity spins,and thus elucidate the intricate interplay between the magnetic anisotropy and YSR multiplets.
基金the NSFC(Grants No.11790313,No.92065201,No.11874256,No.11874258,No.12074247,No.12174252,No.11861161003,No.12025404,No.11904165,No.92161201,No.12104221,and No.12074181)Ministry of Science and Technology of China(Grants No.2019YFA0308600,2020YFA0309000,2017YFA0303203)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Science and Technology Commission of Shanghai Municipality(Grants No.2019SHZDZX01,No.19JC1412701,No.20QA1405100)the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20200312,BK20200310,and BK20190286)or partial support.F.S.Li also acknowledge financial support from the Suzhou Science and Technology Program(Grant No.SJC2021009)and the Youth Innovation Promotion Association of Chinese Academy of Sciences(2017370).
文摘The Mn-Bi-Te class of compounds are recently discovered topological insulators with broken time-reversal-symmetry,which host unique quantum anomalous Hall and axion insulator states.Their key characteristics are believed to be sufficiently understood by models in a single-particle picture.Here,we apply scanning tunneling microscopy to study the electronic properties of MnBi_(2)Te_(4)and MnBi_(4)Te_(7).Unexpectedly,our quasiparticle interference(QPI)results demonstrate that rotational symmetry of the crystal breaks,i.e.a nematic-like pattern arises,in certain energy range but persists in others.Moreover,our data in the presence of an external magnetic field rule out the possibility of the material magnetism as an origin of the C2 symmetric QPI pattern.This study reveals that the interaction in the Mn-Bi-Te class of topological materials may play an essential role in their electronic states,and thus opens a new path for investigating the interplay between wavefunction topology and symmetry breaking phases.
