Transition metal dichalcogenides, featuring layered structures, have aroused enormous interest as a platform for novel physical phenomena and a wide range of potential applications. Among them, special interest has be...Transition metal dichalcogenides, featuring layered structures, have aroused enormous interest as a platform for novel physical phenomena and a wide range of potential applications. Among them, special interest has been placed upon WTe_2 and MoTe_2, which exhibit non-trivial topology both in single layer and bulk as well as pressure induced or enhanced superconductivity. We study another distorted IT material NbTe_2 through systematic electrical transport measurements. Intrinsic superconductivity with onset transition temperature(T_c^(onset)) up to 0.72 K is detected where the upper critical field(H_c) shows unconventional quasi-linear behavior,indicating spin-orbit coupling induced p-wave paring. Furthermore, a general model is proposed to fit the angledependent magnetoresistance, which reveals the Fermi surface anisotropy of NbTe_2. Finally, non-saturating linear magnetoresistance up to 50 T is observed and attributed to the quantum limit transport.展开更多
Wuhan National High Magnetic Field Center(WHMFC)at Huazhong University of Science and Technology is one of the top-class research centers in the world,which can offer pulsed fields up to 90.6 T with different field wa...Wuhan National High Magnetic Field Center(WHMFC)at Huazhong University of Science and Technology is one of the top-class research centers in the world,which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014.This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC.In addition,it will describe the application development of pulsed magnetic fields in both scientific and industrial research.展开更多
We report a study of fermiology,electrical anisotropy,and Fermi liquid properties in the layered ternary boride MoAlB,which could be peeled into two-dimensional(2 D)metal borides(MBenes).By studying the quantum oscill...We report a study of fermiology,electrical anisotropy,and Fermi liquid properties in the layered ternary boride MoAlB,which could be peeled into two-dimensional(2 D)metal borides(MBenes).By studying the quantum oscillations in comprehensive methods of magnetization,magnetothermoelectric power,and torque with the firstprinciple calculations,we reveal three types of bands in this system,including two 2 D-like electronic bands and one complex three-dimensional-like hole band.Meanwhile,a large out-of-plane electrical anisotropy(ρbb/ρaa~1100 andρbb/ρcc~500,at 2 K)was observed,which is similar to those of the typical anisotropic semimetals but lower than those of some semiconductors(up to 10^(5)).After calculating the Kadowaki-Woods ratio(KWR=A/γ^(2)),we observed that the ratio of the in-plane Aa,c/γ^(2)is closer to the universal trend,whereas the out-of-plane Ab/γ^(2)severely deviates from the universality.This demonstrates a 2 D Fermi liquid behavior.In addition,MoAlB cannot be unified using the modified KWR formula like other layered systems(Sr_(2)RuO_(4)and MoOCl_(2)).This unique feature necessitates further exploration of the Fermi liquid property of this layered molybdenum compound.展开更多
In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different...In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and transla- tion speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.展开更多
Unconventional fermions in the immensely studied topological semimetals are the source for rich exotic topological properties.Here,using symmetry analysis and first-principles calculations,we propose the coexistence o...Unconventional fermions in the immensely studied topological semimetals are the source for rich exotic topological properties.Here,using symmetry analysis and first-principles calculations,we propose the coexistence of multiple topological nodal structure in LaSb_(2),including topological nodal surfaces,nodal lines and in particular eightfold degenerate nodal points,which have been scarcely observed in a single material.Further,utilizing angle-resolved photoemission spectroscopy,we confirm the existence of nodal surfaces and eightfold degenerate nodal points in LaSb_(2).The intriguing multiple topological nodal structure might play a crucial role in giving rise to the large linear magnetoresistance.Our work renews the insights into the exotic topological phenomena in LaSb_(2).展开更多
We present a study of electrical and thermal transport in Weyl semimetal WTe_(2)down to 0.3 K.The Wiedemann-Franz law holds below 2 K and a downward deviation starts above.The deviation is more pronounced in cleaner s...We present a study of electrical and thermal transport in Weyl semimetal WTe_(2)down to 0.3 K.The Wiedemann-Franz law holds below 2 K and a downward deviation starts above.The deviation is more pronounced in cleaner samples,as expected in the hydrodynamic picture of electronic transport,where a fraction of electron-electron collisions conserve momentum.Phonons are the dominant heat carriers and their mean-free-path does not display a Knudsen minimum.This is presumably a consequence of weak anharmonicity,as indicated by the temperature dependence of the specific heat.Frequent momentum exchange between phonons and electrons leads to quantum oscillations of the phononic thermal conductivity.Bloch-Grüneisen picture of electron-phonon scattering breaks down at low temperature when Umklapp ph-ph collisions cease to be a sink for electronic flow of momentum.Comparison with semi-metallic Sb shows that normal ph-ph collisions are amplified by anharmonicity.In both semimetals,at cryogenic temperature,e-ph collisions degrade the phononic flow of energy but not the electronic flow of momentum.展开更多
Revolving parts with complex surface structures are widely used in machinery and mechanical equipment. The ECM process provides its adequacy to cut hard materials with different shapes, and its applications are widely...Revolving parts with complex surface structures are widely used in machinery and mechanical equipment. The ECM process provides its adequacy to cut hard materials with different shapes, and its applications are widely increased, due to its outstanding advantages. In this paper, a new method for machining a convex strips structure on a cylinder by using site directed power interruption（SDPI） in the ECM process is presented. A variable correction value of the power-off time was defined and optimized to obtain the ideal interval for better machining accuracy and stability.The electric field distribution and the simulated convex profiles show that the stray current density can be reduced effectively by using the proposed method. The correction value has an important influence on the machining accuracy. A suitable correction value in the range of 0.6–1.2 s can effectively improve the machining accuracy of the convex strips structure. Experiments were also conducted to verify the proposed method. Results have confirmed that the stray corrosion on the convex strips surface is significantly reduced and the machining accuracy of convex strips structure is remarkably improved by using the proposed method with a suitable correction value in the ECM process. Finally, a convex strip with a height of 2 mm on a thin-wall revolving part was also produced successfully using a correction value of 0.9.展开更多
Recently, 12442 system of Fe-based superconductors has attracted considerable attention owing to its unique double-Fe As-layer structure. A steep increase in the in-plane upper critical field with cooling has been obs...Recently, 12442 system of Fe-based superconductors has attracted considerable attention owing to its unique double-Fe As-layer structure. A steep increase in the in-plane upper critical field with cooling has been observed near the superconducting transition temperature, Tc, in KCa2Fe4As4F2 single crystals. Herein, we report a high-field investigation on upper critical field of this material over a wide temperature range, and both out-of-plane(H∥c, Hc2c) and in-plane(H∥ab, Hc2ab ) directions have been measured.A sublinear temperature-dependent behavior is observed for the out-of-plane Hc2c , whereas strong convex curvature with cooling is observed for the in-plane Hc2ab . Such behaviors could not be described by the conventional Werthamer-Helfand-Hohenberg(WHH) model. The data analysis based on the WHH model by considering the spin aspects reveals a large Maki parameter α=9,indicating that the in-plane upper critical field is affected by a very strong Pauli paramagnetic effect.展开更多
The quantum limit, where only the lowest Landau level is occupied by electrons, can be achieved under a high magnetic field when the Landau level splitting is comparable with the Fermi energy. The rather small Fermi p...The quantum limit, where only the lowest Landau level is occupied by electrons, can be achieved under a high magnetic field when the Landau level splitting is comparable with the Fermi energy. The rather small Fermi pockets and Fermi energy in CaFeAsF reported recently make this compound a good candidate for investigating the electrical transport near the quantum limit.Here, we report high-field experiments up to 65 T on a single-crystalline CaFeAsF, which shows a metal-insulator quantum phase transition tuned by the out-of-plane magnetic field. The obtained critical exponent zν through the finite-size scaling analysis is very close to 4/3. This transition is closely associated with the evolution of electronic states approaching the quantum limit.The resistivity behaviors as a function of field and temperature were evaluated based on Adams-Holstein theory(A-H theory).Moreover, the in-plane component of the field, which does not affect the transport behavior in the classical region, suppressed the magnetoresistance near the quantum limit.展开更多
Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper wa...Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper way to tune and manipulate these domain walls. One possible means is through magnetoelastic coupling. The involvement of rare earth in the lately proposed RAl X(R =rare earth, X = Si and Ge) family magnetic Weyl semimetals may provide such a platform. Here we present the transport and thermodynamic properties of Ce Al Ge under hydrostatic pressure. We find that pressure enhances the antiferromagnetic exchange in Ce Al Ge but essentially retains its magnetic structure. A large topological Hall effect with a pronounced loop shape is observed within the magnetically ordered state, and it splits into two regions under pressure. Such an unusual electromagnetic response is inferred to be a consequence of chiral magnetic domain walls. The unprecedented concomitance of its evolution under pressure and the reentrance of antiferromagnetic order strongly suggest the capability of switching on/off this electromagnetic response in noncentrosymmetric magnetic Weyl semimetals via magnetoelastic coupling.展开更多
Rhodium-containing compounds offer a fertile playground to explore novel materials with superconductivity(SC)and other fantastic electronic correlation effects.A new ternary rhodium-antimonide La_(2)Rh_(3)+δSb_(4)(δ...Rhodium-containing compounds offer a fertile playground to explore novel materials with superconductivity(SC)and other fantastic electronic correlation effects.A new ternary rhodium-antimonide La_(2)Rh_(3)+δSb_(4)(δ≈1/8)has been synthesized by a Bi-flux method.It crystallizes in the orthorhombic La_(2)Rh_(3+δ)Sb_(4)-like structure,with the space group Pnma(No.62).The crystalline structure appears as stacking the two-dimensional RhSb_(4)-and RhSb_(5)-polyhedra networks along b axis,and the La atoms embed in the cavities of these networks.Band structure calculations confirm it as a multi-band metal with a van-Hove singularity like feature at the Fermi level,whose density of states are mainly of Rh-4d and Sb-5p characters.The calculations also imply that the redundant Rh acts as charge dopant.SC is observed in this material with onset transition at Ton c≈0.8 K.Ultra-low temperature magnetic susceptibility and specific heat measurements suggest that it is an s-wave type-II superconductor.Our work may also imply that the broad Ln_(2)Tm_(3+δ)Sb_(4)(Ln=rare earth,Tm=Rh,Ir)family may host new material bases where new superconductors,quantum magnetism and other electronic correlation effects could be found.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2018YFA0305600 and 2017YFA0303302the National Natural Science Foundation of China under Grant Nos 11888101,11774008,11704414 and 11427805+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB28000000Beijing Natural Science Foundation(Z180010)
文摘Transition metal dichalcogenides, featuring layered structures, have aroused enormous interest as a platform for novel physical phenomena and a wide range of potential applications. Among them, special interest has been placed upon WTe_2 and MoTe_2, which exhibit non-trivial topology both in single layer and bulk as well as pressure induced or enhanced superconductivity. We study another distorted IT material NbTe_2 through systematic electrical transport measurements. Intrinsic superconductivity with onset transition temperature(T_c^(onset)) up to 0.72 K is detected where the upper critical field(H_c) shows unconventional quasi-linear behavior,indicating spin-orbit coupling induced p-wave paring. Furthermore, a general model is proposed to fit the angledependent magnetoresistance, which reveals the Fermi surface anisotropy of NbTe_2. Finally, non-saturating linear magnetoresistance up to 50 T is observed and attributed to the quantum limit transport.
基金We gratefully acknowledge the financial support of the National Key Research and Development Program of China(2016YFA0401700).
文摘Wuhan National High Magnetic Field Center(WHMFC)at Huazhong University of Science and Technology is one of the top-class research centers in the world,which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014.This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC.In addition,it will describe the application development of pulsed magnetic fields in both scientific and industrial research.
基金supported by the National Natural Science Foundation of China(Grant Nos.12004123,51861135104,and 11574097)the National Key Research and Development Program of China(Grant No.2016YFA0401704)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2019kfy XMBZ071)the China Postdoctoral Science Foundation(Grant No.2018M630846)。
文摘We report a study of fermiology,electrical anisotropy,and Fermi liquid properties in the layered ternary boride MoAlB,which could be peeled into two-dimensional(2 D)metal borides(MBenes).By studying the quantum oscillations in comprehensive methods of magnetization,magnetothermoelectric power,and torque with the firstprinciple calculations,we reveal three types of bands in this system,including two 2 D-like electronic bands and one complex three-dimensional-like hole band.Meanwhile,a large out-of-plane electrical anisotropy(ρbb/ρaa~1100 andρbb/ρcc~500,at 2 K)was observed,which is similar to those of the typical anisotropic semimetals but lower than those of some semiconductors(up to 10^(5)).After calculating the Kadowaki-Woods ratio(KWR=A/γ^(2)),we observed that the ratio of the in-plane Aa,c/γ^(2)is closer to the universal trend,whereas the out-of-plane Ab/γ^(2)severely deviates from the universality.This demonstrates a 2 D Fermi liquid behavior.In addition,MoAlB cannot be unified using the modified KWR formula like other layered systems(Sr_(2)RuO_(4)and MoOCl_(2)).This unique feature necessitates further exploration of the Fermi liquid property of this layered molybdenum compound.
基金Supported by National Natural Science Foundation of China(Grant No.51475239)Program for New Century Excellent Talents in University of China(Grand No.NCET-10-0074)
文摘In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and transla- tion speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406304)the National Natural Science Foundation of China(Grant Nos.U2032208,12222413,11874264,12074181,11834006,and 12104217)+9 种基金the Natural Science Foundation of Shanghai(Grant Nos.23ZR1482200,22ZR1473300,and 14ZR1447600)the Shanghai Science and Technology Innovation Action Plan(Grant No.21JC1402000)the Open Projects from State Key Laboratory of Functional Materials for Informatics(Grant No.SKL2022)the Double First-Class Initiative Fund of Shanghai Tech Universitythe fund of Science and Technology on Surface Physics and Chemistry Laboratory(Grant No.6142A02200102)supported by ME2Project(Grant No.11227902)from the National Natural Science Foundation of Chinasupported by the National Key Projects for Research and Development of China(Grant No.2021YFA1400400)the Fundamental Research Funds for the Central Universities(Grant No.020414380185)the Natural Science Foundation of Jiangsu Province(Grant No.BK20200007)the Fok Ying-Tong Education Foundation of China(Grant No.161006)。
文摘Unconventional fermions in the immensely studied topological semimetals are the source for rich exotic topological properties.Here,using symmetry analysis and first-principles calculations,we propose the coexistence of multiple topological nodal structure in LaSb_(2),including topological nodal surfaces,nodal lines and in particular eightfold degenerate nodal points,which have been scarcely observed in a single material.Further,utilizing angle-resolved photoemission spectroscopy,we confirm the existence of nodal surfaces and eightfold degenerate nodal points in LaSb_(2).The intriguing multiple topological nodal structure might play a crucial role in giving rise to the large linear magnetoresistance.Our work renews the insights into the exotic topological phenomena in LaSb_(2).
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1403500)the National Science Foundation of China(Grant Nos.12004123,51861135104,and 11574097)+3 种基金the Fundamental Research Funds for the Central Universities(Grant No.2019kfy XMBZ071)supported by the Agence Nationale de la Recherche(Grant No.ANR-19-CE30-0014-04)the China National Postdoctoral Program for Innovative Talents(Grant No.BX20200143)the China Postdoctoral Science Foundation(Grant No.2020M682386)。
文摘We present a study of electrical and thermal transport in Weyl semimetal WTe_(2)down to 0.3 K.The Wiedemann-Franz law holds below 2 K and a downward deviation starts above.The deviation is more pronounced in cleaner samples,as expected in the hydrodynamic picture of electronic transport,where a fraction of electron-electron collisions conserve momentum.Phonons are the dominant heat carriers and their mean-free-path does not display a Knudsen minimum.This is presumably a consequence of weak anharmonicity,as indicated by the temperature dependence of the specific heat.Frequent momentum exchange between phonons and electrons leads to quantum oscillations of the phononic thermal conductivity.Bloch-Grüneisen picture of electron-phonon scattering breaks down at low temperature when Umklapp ph-ph collisions cease to be a sink for electronic flow of momentum.Comparison with semi-metallic Sb shows that normal ph-ph collisions are amplified by anharmonicity.In both semimetals,at cryogenic temperature,e-ph collisions degrade the phononic flow of energy but not the electronic flow of momentum.
基金supports provided by the State Key Program of the National Natural Science Foundation of China(No.51535006)Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology of China
文摘Revolving parts with complex surface structures are widely used in machinery and mechanical equipment. The ECM process provides its adequacy to cut hard materials with different shapes, and its applications are widely increased, due to its outstanding advantages. In this paper, a new method for machining a convex strips structure on a cylinder by using site directed power interruption（SDPI） in the ECM process is presented. A variable correction value of the power-off time was defined and optimized to obtain the ideal interval for better machining accuracy and stability.The electric field distribution and the simulated convex profiles show that the stray current density can be reduced effectively by using the proposed method. The correction value has an important influence on the machining accuracy. A suitable correction value in the range of 0.6–1.2 s can effectively improve the machining accuracy of the convex strips structure. Experiments were also conducted to verify the proposed method. Results have confirmed that the stray corrosion on the convex strips surface is significantly reduced and the machining accuracy of convex strips structure is remarkably improved by using the proposed method with a suitable correction value in the ECM process. Finally, a convex strip with a height of 2 mm on a thin-wall revolving part was also produced successfully using a correction value of 0.9.
基金supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2015187)the National Natural Science Foundation of China(Grant Nos.11204338,11704385,and11874359)the “Strategic Priority Research Program(B)” of the Chinese Academy of Sciences(Grant No.XDB04040300)
文摘Recently, 12442 system of Fe-based superconductors has attracted considerable attention owing to its unique double-Fe As-layer structure. A steep increase in the in-plane upper critical field with cooling has been observed near the superconducting transition temperature, Tc, in KCa2Fe4As4F2 single crystals. Herein, we report a high-field investigation on upper critical field of this material over a wide temperature range, and both out-of-plane(H∥c, Hc2c) and in-plane(H∥ab, Hc2ab ) directions have been measured.A sublinear temperature-dependent behavior is observed for the out-of-plane Hc2c , whereas strong convex curvature with cooling is observed for the in-plane Hc2ab . Such behaviors could not be described by the conventional Werthamer-Helfand-Hohenberg(WHH) model. The data analysis based on the WHH model by considering the spin aspects reveals a large Maki parameter α=9,indicating that the in-plane upper critical field is affected by a very strong Pauli paramagnetic effect.
基金supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant Nos. 2015187, and 2016215)National Natural Science Foundation of China (Grant Nos. 11574338, 11204338, and 11404359)and the ”Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04040300)
文摘The quantum limit, where only the lowest Landau level is occupied by electrons, can be achieved under a high magnetic field when the Landau level splitting is comparable with the Fermi energy. The rather small Fermi pockets and Fermi energy in CaFeAsF reported recently make this compound a good candidate for investigating the electrical transport near the quantum limit.Here, we report high-field experiments up to 65 T on a single-crystalline CaFeAsF, which shows a metal-insulator quantum phase transition tuned by the out-of-plane magnetic field. The obtained critical exponent zν through the finite-size scaling analysis is very close to 4/3. This transition is closely associated with the evolution of electronic states approaching the quantum limit.The resistivity behaviors as a function of field and temperature were evaluated based on Adams-Holstein theory(A-H theory).Moreover, the in-plane component of the field, which does not affect the transport behavior in the classical region, suppressed the magnetoresistance near the quantum limit.
基金supported by the Open Research Fund of Songshan Lake Materials Laboratory(Grant No.2022SLABFN27)National Natural Science Foundation of China(Grant Nos.12274364,and U1932155)+3 种基金Fundamental Research Funds for the Central Universities of China(Grant No.2019kfy XMBZ071)National Key R&D Program of China(Grant No.2022YFA1602602)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022B1515120020)Pioneer and Leading Goose R&D Program of Zhejiang(Grant No.2022SDXHDX0005)。
文摘Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper way to tune and manipulate these domain walls. One possible means is through magnetoelastic coupling. The involvement of rare earth in the lately proposed RAl X(R =rare earth, X = Si and Ge) family magnetic Weyl semimetals may provide such a platform. Here we present the transport and thermodynamic properties of Ce Al Ge under hydrostatic pressure. We find that pressure enhances the antiferromagnetic exchange in Ce Al Ge but essentially retains its magnetic structure. A large topological Hall effect with a pronounced loop shape is observed within the magnetically ordered state, and it splits into two regions under pressure. Such an unusual electromagnetic response is inferred to be a consequence of chiral magnetic domain walls. The unprecedented concomitance of its evolution under pressure and the reentrance of antiferromagnetic order strongly suggest the capability of switching on/off this electromagnetic response in noncentrosymmetric magnetic Weyl semimetals via magnetoelastic coupling.
基金This work was supported by the open research fund of Songshan Lake Materials Laboratory(2022SLABFN27)NSF of China(Grants Nos.12004270,51861135104,11574097,12204298,12274364 and 11874137)+2 种基金the Fundamental Research Funds for the Central Universities of China(2019kfyXMBZ071)Guangdong Basic and Applied Basic Research Foundation(2019A1515110517)the Pioneer and Leading Goose R&D Program of Zhejiang(2022SDXHDX0005).
文摘Rhodium-containing compounds offer a fertile playground to explore novel materials with superconductivity(SC)and other fantastic electronic correlation effects.A new ternary rhodium-antimonide La_(2)Rh_(3)+δSb_(4)(δ≈1/8)has been synthesized by a Bi-flux method.It crystallizes in the orthorhombic La_(2)Rh_(3+δ)Sb_(4)-like structure,with the space group Pnma(No.62).The crystalline structure appears as stacking the two-dimensional RhSb_(4)-and RhSb_(5)-polyhedra networks along b axis,and the La atoms embed in the cavities of these networks.Band structure calculations confirm it as a multi-band metal with a van-Hove singularity like feature at the Fermi level,whose density of states are mainly of Rh-4d and Sb-5p characters.The calculations also imply that the redundant Rh acts as charge dopant.SC is observed in this material with onset transition at Ton c≈0.8 K.Ultra-low temperature magnetic susceptibility and specific heat measurements suggest that it is an s-wave type-II superconductor.Our work may also imply that the broad Ln_(2)Tm_(3+δ)Sb_(4)(Ln=rare earth,Tm=Rh,Ir)family may host new material bases where new superconductors,quantum magnetism and other electronic correlation effects could be found.
