The nontrivial band topologies protected by certain symmetries have attracted significant interest in condensed matter physics.The discoveries of nontrivial topological phases in real materials provide a series of arc...The nontrivial band topologies protected by certain symmetries have attracted significant interest in condensed matter physics.The discoveries of nontrivial topological phases in real materials provide a series of archetype materials to further explore the topological physics.展开更多
The simple kagome-lattice band structure possesses Dirac cones,flat band,and saddle point with van Hove singularities in the electronic density of states,facilitating the emergence of various electronic orders.Here we...The simple kagome-lattice band structure possesses Dirac cones,flat band,and saddle point with van Hove singularities in the electronic density of states,facilitating the emergence of various electronic orders.Here we report a titanium-based kagome metal CsTi_(3)Bi_(5)where titanium atoms form a kagome network,resembling its isostructural compound CsV_3Sb_5.Thermodynamic properties including the magnetization,resistance,and heat capacity reveal the conventional Fermi liquid behavior in the kagome metal CsTi_(3)Bi_(5)and no signature of superconducting or charge density wave(CDW)transition anomaly down to 85 m K.Systematic angle-resolved photoemission spectroscopy measurements reveal multiple bands crossing the Fermi level,consistent with the first-principles calculations.The flat band formed by the destructive interference of hopping in the kagome lattice is observed directly.Compared to Cs V_(3)Sb_(5),the van Hove singularities are pushed far away above the Fermi level in CsTi_(3)Bi_(5),in line with the absence of CDW.Furthermore,the first-principles calculations identify the nontrivial Z_(2)topological properties for those bands crossing the Fermi level,accompanied by several local band inversions.Our results suppose CsTi_(3)Bi_(5)as a complementary platform to explore the superconductivity and nontrivial band topology.展开更多
The b-family fifth-order Camassa–Holm model is a nontrivial extension of the celebrated Camassa–Holm model. This work investigates single-pseudo and multi-pseudo peakon solutions of this model via analytical calcula...The b-family fifth-order Camassa–Holm model is a nontrivial extension of the celebrated Camassa–Holm model. This work investigates single-pseudo and multi-pseudo peakon solutions of this model via analytical calculations and numerical simulations. Some intriguing phenomena of multi-pseudo peakon which do not appear in the classical Camassa–Holm model interactions are observed, such as two-pseudo peakon collapses, threepseudo peakon resonance, and multi-pseudo peakon inelastic collisions. The present work will inspire further studies on the higher-dimensional integrable Camassa–Holm systems which may have high value in investigating the related higher-dimensional physical problems.展开更多
The kagome superconductor with a twodimensional corner-sharing triangular lattice has attracted tremendous attention due to the interplay between nontrivial band topology,anomalous Hall effect(AHE),charge density wave...The kagome superconductor with a twodimensional corner-sharing triangular lattice has attracted tremendous attention due to the interplay between nontrivial band topology,anomalous Hall effect(AHE),charge density waves(CDW),pair density wave(PDW),electronic nematicity and unconventional superconductivity.All these exotic quantum phenomena are thought to originate from the unique electronic structure of the kagome lattice including flat bands,Dirac cones and van Hove singularities.展开更多
In this article, the authors prove the existence and the nonexistence of nontrivial solutions for a semilinear biharmonic equation involving critical exponent by virtue of Mountain Pass Lemma and Sobolev-Hardy inequal...In this article, the authors prove the existence and the nonexistence of nontrivial solutions for a semilinear biharmonic equation involving critical exponent by virtue of Mountain Pass Lemma and Sobolev-Hardy inequality.展开更多
In this paper, we prove the existence of at least one positive solution pair (u, v)∈ H1(RN) × H1(RN) to the following semilinear elliptic system {-△u+u=f(x,v),x∈RN,-△u+u=g(x,v),x∈RN (0.1),by us...In this paper, we prove the existence of at least one positive solution pair (u, v)∈ H1(RN) × H1(RN) to the following semilinear elliptic system {-△u+u=f(x,v),x∈RN,-△u+u=g(x,v),x∈RN (0.1),by using a linking theorem and the concentration-compactness principle. The main conditions we imposed on the nonnegative functions f, g ∈C0(RN× R1) are that, f(x, t) and g(x, t) are superlinear at t = 0 as well as at t =+∞, that f and g are subcritical in t and satisfy a kind of monotonic conditions. We mention that we do not assume that f or g satisfies the Ambrosetti-Rabinowitz condition as usual. Our main result can be viewed as an extension to a recent result of Miyagaki and Souto [J. Diff. Equ. 245(2008), 3628-3638] concerning the existence of a positive solution to the semilinear elliptic boundary value problem {-△u+u=f(x,u),x∈Ω,u∈H0^1(Ω) where Ω ∩→RN is bounded and a result of Li and Yang [G. Li and J. Yang: Communications in P.D.E. Vol. 29(2004) Nos.5& 6.pp.925-954, 2004] concerning (0.1) when f and g are asymptotically linear.展开更多
In this article, we consider a class of degenerate quasilinear elliptic problems with weights and nonlinearity involving the critical Hardy-Sobolev exponent and one sign- changing function. The existence and multiplic...In this article, we consider a class of degenerate quasilinear elliptic problems with weights and nonlinearity involving the critical Hardy-Sobolev exponent and one sign- changing function. The existence and multiplicity results of positive solutions are obtained by variational methods.展开更多
Some theorems are obtained for the existence of nontrivial solutions of Hamiltonian systems with Lagrangian boundary conditions by the minimax methods.
Recently,natural van der Waals heterostructures of(MnBi2 Te4)m(Bi2 Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states.We sy...Recently,natural van der Waals heterostructures of(MnBi2 Te4)m(Bi2 Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states.We systematically investigate both the structural and electronic responses of MnBi2 Te4 and MnBi4 Te7 to external pressure.In addition to the suppression of antiferromagnetic order,MnBi2 Te4 is found to undergo a metalsemiconductor-metal transition upon compression.The resistivity of MnBi4 Te7 changes dramatically under high pressure and a non-monotonic evolution of p(T)is observed.The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime.We find that the bulk and surface states respond differently to pressure,which is consistent with the non-monotonic change of the resistivity.Interestingly,a pressure-induced amorphous state is observed in MnBi2 Te4,while two high-pressure phase transitions are revealed in MnBi4 Te7.Our combined theoretical and experimental research establishes MnBi2 Te4 and MnBi4 Te7 as highly tunable magnetic topological insulators,in which phase transitions and new ground states emerge upon compression.展开更多
In this article, we are concerned with the existence of solutions of a quasilinear elliptic equation in R^N which includes the so-called modified nonlinear Schrodinger equation as a special case. Combining the dual ap...In this article, we are concerned with the existence of solutions of a quasilinear elliptic equation in R^N which includes the so-called modified nonlinear Schrodinger equation as a special case. Combining the dual approach and the nonsmooth critical point theory, we obtain the existence of a nontrivial solution.展开更多
We study nonautonomonus second order periodic systems with a nonslnooth potential. Using the nonsmooth critical theory, we establish the existence of at least two nontrivial solutions. Our framework incorporates large...We study nonautonomonus second order periodic systems with a nonslnooth potential. Using the nonsmooth critical theory, we establish the existence of at least two nontrivial solutions. Our framework incorporates large classes of both subquadratic and superquadratic potentials at infinity.展开更多
Structure of nonnegative nontrivial and positive solutions was precisely studied for some singularly perturbed p-Laplace equations. By virtue of sub- and supersolution method, it is shown that there are many nonnegati...Structure of nonnegative nontrivial and positive solutions was precisely studied for some singularly perturbed p-Laplace equations. By virtue of sub- and supersolution method, it is shown that there are many nonnegative nontrivial spike-layer solutions and positive intermediate spike-layer solutions. Moreover, the upper and lower bound on the measure of each spike-layer were estimated when the parameter is sufficiently small.展开更多
In this paper, for a second-order three-point boundary value problem u″+f(t,u)=0,0〈t〈1,au(0)-bu′(0)=0,u(1)-au(η)=0,where η∈ (0, 1), a, b, α ∈R with a^2 + b^2 〉 0, the existence of its nontrivia...In this paper, for a second-order three-point boundary value problem u″+f(t,u)=0,0〈t〈1,au(0)-bu′(0)=0,u(1)-au(η)=0,where η∈ (0, 1), a, b, α ∈R with a^2 + b^2 〉 0, the existence of its nontrivial solution is studied. The'conditions on f which guarantee the existence of nontrivial solution are formulated. As an application, some examples to demonstrate the results are given.展开更多
In this paper, we establish the existence of at least five distinct solutions to a p-Laplacian problems involving critical exponents and singular cylindrical potential, by using the Nehari manifold, concentration-comp...In this paper, we establish the existence of at least five distinct solutions to a p-Laplacian problems involving critical exponents and singular cylindrical potential, by using the Nehari manifold, concentration-compactness principle and mountain pass theorem展开更多
Disorder inevitably exists in realistic samples,manifesting itself in various exotic properties for the topological states.In this paper,we summarize and briefly review the work completed over the last few years,inclu...Disorder inevitably exists in realistic samples,manifesting itself in various exotic properties for the topological states.In this paper,we summarize and briefly review the work completed over the last few years,including our own,regarding recent developments in several topics about disorder effects in topological states.For weak disorder,the robustness of topological states is demonstrated,especially for both quantum spin Hall states with Z2 = 1 and size induced nontrivial topological insulators with Z2 = 0.For moderate disorder,by increasing the randomness of both the impurity distribution and the impurity induced potential,the topological insulator states can be created from normal metallic or insulating states.These phenomena and their mechanisms are summarized.For strong disorder,the disorder causes a metal-insulator transition.Due to their topological nature,the phase diagrams are much richer in topological state systems.Finally,the trends in these areas of disorder research are discussed.展开更多
One parabolic p-Laplacian-like differential equation with mixed boundaries is au/at in the corresponding studies is replaced by a(au/at), studied in this paper, where the item au/at which makes it more general. The...One parabolic p-Laplacian-like differential equation with mixed boundaries is au/at in the corresponding studies is replaced by a(au/at), studied in this paper, where the item au/at which makes it more general. The sufficient condition of the existence and uniqueness of non-trivial solution in L2(O, T; L2 (Ω)) is presented by employing the techniques of splitting the boundary problems into operator equation. Compared to the corresponding work, the restrictions imposed on the equation are weaken and the proof technique is simplified. It can be regarded as the extension and complement of the previous work.展开更多
In this paper, we are concerned with the following problem:{(-△)ku=λf(x)|u|q-2u+g(x)|u|k*-2u, x∈Ω, u∈H k0 (Ω), where Ωis a bounded domain in RN with N ≥2k+1, 1〈q〈2,λ〉0, f, g are continuous ...In this paper, we are concerned with the following problem:{(-△)ku=λf(x)|u|q-2u+g(x)|u|k*-2u, x∈Ω, u∈H k0 (Ω), where Ωis a bounded domain in RN with N ≥2k+1, 1〈q〈2,λ〉0, f, g are continuous functions on Ω which are somewhere positive but which may change sign on Ω. k* = N2/N-2k is the critical Sobolev exponent. By extracting the Palais-Smale sequence in the Nehari manifold, the existence of multiple nontrivial solutions to this equation is verified.展开更多
As a new type of quantum state of matter hosting low energy relativistic quasiparticles,Weyl semimetals(WSMs)have attracted significant attention for scientific community and potential quantum device applications.In t...As a new type of quantum state of matter hosting low energy relativistic quasiparticles,Weyl semimetals(WSMs)have attracted significant attention for scientific community and potential quantum device applications.In this study,we present a comprehensive investigation of the structural,magnetic,and transport properties of noncentrosymmetric RAl Si(R=Sm,Ce),which have been predicted to be new magnetic WSM candidates.Both samples exhibit nonsaturated magnetoresistance,with about 900%and 80%for Sm Al Si and Ce Al Si,respectively,at temperature of 1.8 K and magnetic field of 9 T.The carrier densities of Sm Al Si and Ce Al Si exhibit remarkable change around magnetic transition temperatures,signifying that the electronic states are sensitive to the magnetic ordering of rare-earth elements.At low temperatures,Sm Al Si reveals prominent Shubnikov–de Haas oscillations associated with the nontrivial Berry phase.High-pressure experiments demonstrate that the magnetic order is robust and survival under high pressure.Our results would yield valuable insights into WSM physics and potentials in applications to next-generation spintronic devices in the RAl Si(R=Sm,Ce)family.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12374159 and 11974076)the Key Project of Natural Science Foundation of Fujian Province,China(Grant No.2021J02012)+1 种基金the GHfund A(Grant No.202302019222)the Research Foundation of the Academy of Carbon Neutrality of Fujian Normal University,China(Grant No.TZH2022-05)。
文摘The nontrivial band topologies protected by certain symmetries have attracted significant interest in condensed matter physics.The discoveries of nontrivial topological phases in real materials provide a series of archetype materials to further explore the topological physics.
基金the National Key R&D Program of China(Grant No.2022YFA1403700)the National Natural Science Foundation of China(Grant Nos.12074163 and 12004030)+5 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022B1515020046,2022B1515130005,2021B1515130007,and 2020B1515120100)the Guangdong Innovative and Entrepreneurial Research Team Program(Grant Nos.2017ZT07C062 and 2019ZT08C044)the Shenzhen Science and Technology Program(Grant No.KQTD20190929173815000)Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices(Grant No.ZDSYS20190902092905285)the Shenzhen Fundamental Research Program(Grant No.JCYJ20220818100405013)China Postdoctoral Science Foundation(Grant No.2020M682780 and 2022M711495)。
文摘The simple kagome-lattice band structure possesses Dirac cones,flat band,and saddle point with van Hove singularities in the electronic density of states,facilitating the emergence of various electronic orders.Here we report a titanium-based kagome metal CsTi_(3)Bi_(5)where titanium atoms form a kagome network,resembling its isostructural compound CsV_3Sb_5.Thermodynamic properties including the magnetization,resistance,and heat capacity reveal the conventional Fermi liquid behavior in the kagome metal CsTi_(3)Bi_(5)and no signature of superconducting or charge density wave(CDW)transition anomaly down to 85 m K.Systematic angle-resolved photoemission spectroscopy measurements reveal multiple bands crossing the Fermi level,consistent with the first-principles calculations.The flat band formed by the destructive interference of hopping in the kagome lattice is observed directly.Compared to Cs V_(3)Sb_(5),the van Hove singularities are pushed far away above the Fermi level in CsTi_(3)Bi_(5),in line with the absence of CDW.Furthermore,the first-principles calculations identify the nontrivial Z_(2)topological properties for those bands crossing the Fermi level,accompanied by several local band inversions.Our results suppose CsTi_(3)Bi_(5)as a complementary platform to explore the superconductivity and nontrivial band topology.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12371247 and 11971067)。
文摘The b-family fifth-order Camassa–Holm model is a nontrivial extension of the celebrated Camassa–Holm model. This work investigates single-pseudo and multi-pseudo peakon solutions of this model via analytical calculations and numerical simulations. Some intriguing phenomena of multi-pseudo peakon which do not appear in the classical Camassa–Holm model interactions are observed, such as two-pseudo peakon collapses, threepseudo peakon resonance, and multi-pseudo peakon inelastic collisions. The present work will inspire further studies on the higher-dimensional integrable Camassa–Holm systems which may have high value in investigating the related higher-dimensional physical problems.
文摘The kagome superconductor with a twodimensional corner-sharing triangular lattice has attracted tremendous attention due to the interplay between nontrivial band topology,anomalous Hall effect(AHE),charge density waves(CDW),pair density wave(PDW),electronic nematicity and unconventional superconductivity.All these exotic quantum phenomena are thought to originate from the unique electronic structure of the kagome lattice including flat bands,Dirac cones and van Hove singularities.
基金Supported by NSFC(10471047)NSF Guangdong Province(05300159).
文摘In this article, the authors prove the existence and the nonexistence of nontrivial solutions for a semilinear biharmonic equation involving critical exponent by virtue of Mountain Pass Lemma and Sobolev-Hardy inequality.
基金supported by NSFC (10571069, 10631030) and Hubei Key Laboratory of Mathematical Sciencessupported by the fund of CCNU for PHD students(2009019)
文摘In this paper, we prove the existence of at least one positive solution pair (u, v)∈ H1(RN) × H1(RN) to the following semilinear elliptic system {-△u+u=f(x,v),x∈RN,-△u+u=g(x,v),x∈RN (0.1),by using a linking theorem and the concentration-compactness principle. The main conditions we imposed on the nonnegative functions f, g ∈C0(RN× R1) are that, f(x, t) and g(x, t) are superlinear at t = 0 as well as at t =+∞, that f and g are subcritical in t and satisfy a kind of monotonic conditions. We mention that we do not assume that f or g satisfies the Ambrosetti-Rabinowitz condition as usual. Our main result can be viewed as an extension to a recent result of Miyagaki and Souto [J. Diff. Equ. 245(2008), 3628-3638] concerning the existence of a positive solution to the semilinear elliptic boundary value problem {-△u+u=f(x,u),x∈Ω,u∈H0^1(Ω) where Ω ∩→RN is bounded and a result of Li and Yang [G. Li and J. Yang: Communications in P.D.E. Vol. 29(2004) Nos.5& 6.pp.925-954, 2004] concerning (0.1) when f and g are asymptotically linear.
文摘In this article, we consider a class of degenerate quasilinear elliptic problems with weights and nonlinearity involving the critical Hardy-Sobolev exponent and one sign- changing function. The existence and multiplicity results of positive solutions are obtained by variational methods.
基金supported by the National Natural Science Foundation of China and 973 Program of STM.
文摘Some theorems are obtained for the existence of nontrivial solutions of Hamiltonian systems with Lagrangian boundary conditions by the minimax methods.
基金Supported by the National Key Research and Development Program of China under Grant Nos.2018YFA0704300 and2017YFE0131300the National Natural Science Foundation of China under Grant Nos.U1932217,11974246,11874263 and10225417+1 种基金the Natural Science Foundation of Shanghai under Grant No.19ZR1477300the support from Analytical Instrumentation Center(SPST-AIC10112914),SPST,ShanghaiTech Universitysupported by Collaborative Research Project of Materials and Structures Laboratory,Tokyo Institute of Technology,Japan,Part of this research is supported by COMPRES(NSF Cooperative Agreement EAR-1661511)。
文摘Recently,natural van der Waals heterostructures of(MnBi2 Te4)m(Bi2 Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states.We systematically investigate both the structural and electronic responses of MnBi2 Te4 and MnBi4 Te7 to external pressure.In addition to the suppression of antiferromagnetic order,MnBi2 Te4 is found to undergo a metalsemiconductor-metal transition upon compression.The resistivity of MnBi4 Te7 changes dramatically under high pressure and a non-monotonic evolution of p(T)is observed.The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime.We find that the bulk and surface states respond differently to pressure,which is consistent with the non-monotonic change of the resistivity.Interestingly,a pressure-induced amorphous state is observed in MnBi2 Te4,while two high-pressure phase transitions are revealed in MnBi4 Te7.Our combined theoretical and experimental research establishes MnBi2 Te4 and MnBi4 Te7 as highly tunable magnetic topological insulators,in which phase transitions and new ground states emerge upon compression.
基金supported partially by National Natural Science Foundation of China(11771385,11661083)the Youth Foundation of Yunnan Minzu University(2017QNo3)
文摘In this article, we are concerned with the existence of solutions of a quasilinear elliptic equation in R^N which includes the so-called modified nonlinear Schrodinger equation as a special case. Combining the dual approach and the nonsmooth critical point theory, we obtain the existence of a nontrivial solution.
基金supported by the State Committee for Scientific Research of Poland (KBN) under research grants nr 2 P03A 003 25 and nr 4T07A 027 26
文摘We study nonautonomonus second order periodic systems with a nonslnooth potential. Using the nonsmooth critical theory, we establish the existence of at least two nontrivial solutions. Our framework incorporates large classes of both subquadratic and superquadratic potentials at infinity.
文摘Structure of nonnegative nontrivial and positive solutions was precisely studied for some singularly perturbed p-Laplace equations. By virtue of sub- and supersolution method, it is shown that there are many nonnegative nontrivial spike-layer solutions and positive intermediate spike-layer solutions. Moreover, the upper and lower bound on the measure of each spike-layer were estimated when the parameter is sufficiently small.
基金This work was supported by Key Academic Discipline of Zhejiang Province of China(2005)the Natural Science Foundation of Zhejiang Province of China(Y605144)the Education Department of Zhejiang Province of China(20051897).
文摘In this paper, for a second-order three-point boundary value problem u″+f(t,u)=0,0〈t〈1,au(0)-bu′(0)=0,u(1)-au(η)=0,where η∈ (0, 1), a, b, α ∈R with a^2 + b^2 〉 0, the existence of its nontrivial solution is studied. The'conditions on f which guarantee the existence of nontrivial solution are formulated. As an application, some examples to demonstrate the results are given.
文摘In this paper, we establish the existence of at least five distinct solutions to a p-Laplacian problems involving critical exponents and singular cylindrical potential, by using the Nehari manifold, concentration-compactness principle and mountain pass theorem
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11374219,11474085,and 11534001)the Natural Science Foundation of Jiangsu Province,China(Grant No BK20160007)
文摘Disorder inevitably exists in realistic samples,manifesting itself in various exotic properties for the topological states.In this paper,we summarize and briefly review the work completed over the last few years,including our own,regarding recent developments in several topics about disorder effects in topological states.For weak disorder,the robustness of topological states is demonstrated,especially for both quantum spin Hall states with Z2 = 1 and size induced nontrivial topological insulators with Z2 = 0.For moderate disorder,by increasing the randomness of both the impurity distribution and the impurity induced potential,the topological insulator states can be created from normal metallic or insulating states.These phenomena and their mechanisms are summarized.For strong disorder,the disorder causes a metal-insulator transition.Due to their topological nature,the phase diagrams are much richer in topological state systems.Finally,the trends in these areas of disorder research are discussed.
基金supported by the National Natural Science Foundation of China(11071053)Natural Science Foundation of Hebei Province(A2014207010)+1 种基金Key Project of Science and Research of Hebei Educational Department(ZD2016024)Key Project of Science and Research of Hebei University of Economics and Business(2015KYZ03)
文摘One parabolic p-Laplacian-like differential equation with mixed boundaries is au/at in the corresponding studies is replaced by a(au/at), studied in this paper, where the item au/at which makes it more general. The sufficient condition of the existence and uniqueness of non-trivial solution in L2(O, T; L2 (Ω)) is presented by employing the techniques of splitting the boundary problems into operator equation. Compared to the corresponding work, the restrictions imposed on the equation are weaken and the proof technique is simplified. It can be regarded as the extension and complement of the previous work.
基金supported by the National Natural Science Foundation of China(11326139,11326145)Tian Yuan Foundation(KJLD12067)+1 种基金Central Specialized Fundation of SCUEC(CZQ13013)the Project of Jiangxi Province Technology Hall(2014BAB211010)
文摘In this paper, we are concerned with the following problem:{(-△)ku=λf(x)|u|q-2u+g(x)|u|k*-2u, x∈Ω, u∈H k0 (Ω), where Ωis a bounded domain in RN with N ≥2k+1, 1〈q〈2,λ〉0, f, g are continuous functions on Ω which are somewhere positive but which may change sign on Ω. k* = N2/N-2k is the critical Sobolev exponent. By extracting the Palais-Smale sequence in the Nehari manifold, the existence of multiple nontrivial solutions to this equation is verified.
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0704300 and 2017YFB0503302)the National Natural Science Foundation of China(Grant Nos.U1932217,11974246,12004252,61771234,and 12004251)+6 种基金the Natural Science Foundation of Shanghai(Grant Nos.19ZR1477300 and 20ZR1436100)the Science and Technology Commission of Shanghai Municipality(Grant Nos.19JC1413900 and YDZX20203100001438)the Shanghai Science and Technology Plan(Grant No.21DZ2260400),the Shanghai Sailing Program(Grant No.21YF1429200)the Interdisciplinary Program of Wuhan National High Magnetic Field Center(Grant No.WHMFC202124)the Beijing National Laboratory for Condensed Matter Physicsthe support from Analytical Instrumentation Center(Grant No.SPST-AIC10112914)Centre for High-resolution Electron Microscopy(ChEM)(Grant No.EM02161943),SPST,Shanghai Tech University。
文摘As a new type of quantum state of matter hosting low energy relativistic quasiparticles,Weyl semimetals(WSMs)have attracted significant attention for scientific community and potential quantum device applications.In this study,we present a comprehensive investigation of the structural,magnetic,and transport properties of noncentrosymmetric RAl Si(R=Sm,Ce),which have been predicted to be new magnetic WSM candidates.Both samples exhibit nonsaturated magnetoresistance,with about 900%and 80%for Sm Al Si and Ce Al Si,respectively,at temperature of 1.8 K and magnetic field of 9 T.The carrier densities of Sm Al Si and Ce Al Si exhibit remarkable change around magnetic transition temperatures,signifying that the electronic states are sensitive to the magnetic ordering of rare-earth elements.At low temperatures,Sm Al Si reveals prominent Shubnikov–de Haas oscillations associated with the nontrivial Berry phase.High-pressure experiments demonstrate that the magnetic order is robust and survival under high pressure.Our results would yield valuable insights into WSM physics and potentials in applications to next-generation spintronic devices in the RAl Si(R=Sm,Ce)family.