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Nomoto T, Imajo S, Akutsu H, Nakazawa Y, Kohama Y. Correlation-driven organic 3D topological insulator with relativistic fermions. Nat Commun 2023; 14:2130. [PMID: 37080975 PMCID: PMC10119126 DOI: 10.1038/s41467-023-37293-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/09/2023] [Indexed: 04/22/2023] Open
Abstract
Exploring new topological phenomena and functionalities induced by strong electron correlation has been a central issue in modern condensed-matter physics. One example is a topological insulator (TI) state and its functionality driven by the Coulomb repulsion rather than a spin-orbit coupling. Here, we report a 'correlation-driven' TI state realized in an organic zero-gap system α-(BETS)2I3. The topological surface state and chiral anomaly are observed in temperature and field dependences of resistance, indicating a three-dimensional TI state at low temperatures. Moreover, we observe a topological phase switching between the TI state and non-equilibrium Dirac semimetal state by a dc current, which is a unique functionality of a correlation-driven TI state. Our findings demonstrate that correlation-driven TIs are promising candidates not only for practical electronic devices but also as a field for discovering new topological phenomena and phases.
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Affiliation(s)
- Tetsuya Nomoto
- The Institute for Solid State Physics, the University of Tokyo, Kashiwa, Chiba, 277-8581, Japan.
- Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
| | - Shusaku Imajo
- The Institute for Solid State Physics, the University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Hiroki Akutsu
- Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Yasuhiro Nakazawa
- Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Yoshimitsu Kohama
- The Institute for Solid State Physics, the University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
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2
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Zhao H, Li W, Chen Y, Xu C, Li B, Luo W, Qian D, Shi Z. Transport property of multi-band topological material PtBi[Formula: see text] studied by maximum entropy mobility spectrum analysis (MEMSA). Sci Rep 2021; 11:6249. [PMID: 33737569 PMCID: PMC7973776 DOI: 10.1038/s41598-021-85364-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 02/26/2021] [Indexed: 12/03/2022] Open
Abstract
Electrical transport of both longitudinal and transverse directions carries rich information. Mobility spectrum analysis (MSA) is capable of extracting charge information from conductivity tensor, including charge types, concentration and mobilities. Using a numerical method based on maximum entropy principle, i.e., maximum entropy mobility spectrum analysis (MEMSA), mobility spectrum for [Formula: see text]-type PtBi[Formula: see text] is studied. Three hole-pockets and two electron-pockets were found, including a small hole pocket with very high mobility, which is very likely corresponding to Dirac Fermions. Benefiting from our high resolution result, we studied temperature dependence of carrier properties and explained the sign change phenomenon of Hall conductivity. We further compared the results with band structure obtained by our first principle calculation. The present results prove MEMSA is a useful tool of extracting carries' information in recently discovered Iron-based superconductors, and topological materials.
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Affiliation(s)
- Haijun Zhao
- School of Physics, Southeast University, Nanjing, 211189 China
| | - Wenchong Li
- School of Physics, Southeast University, Nanjing, 211189 China
| | - Yue Chen
- School of Physics, Southeast University, Nanjing, 211189 China
| | - Chunqiang Xu
- School of Physics, Southeast University, Nanjing, 211189 China
| | - Bin Li
- Information Physics Research Center, Nanjing University of Posts and Telecommunications, Nanjing, 210023 China
| | - Weidong Luo
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240 China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Dong Qian
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240 China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Zhixiang Shi
- School of Physics, Southeast University, Nanjing, 211189 China
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3
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Zhu Q, Mao Q, Xu B, Du J, Chen M, Yang J, Chen B, Cao C, Wang H, Fang M. Large magnetoresistance and large magnetothermopower effect in the Dirac material EuMn 0.8Sb 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:185701. [PMID: 30721896 DOI: 10.1088/1361-648x/ab0482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this article, the structure, transport and magnetic properties were studied in details for EuMn0.8Sb2 crystals with the orthorhombic structure and Mn deficiencies. It was found that the temperature dependence of the resistivity exhibits a metallic behavior in the whole measuring temperature range, different from that in the crystals without Mn deficiencies. A large positive magnetoresistance (MR) (∼127% at 2 K and ∼25% at 300 K, in 9 T field) was observed, which can be ascribed to the combination of semiclassical MR and quantum limit MR of Dirac electrons. We also observed the high mobility of the carriers and large magnetothermopower effect at low temperatures, and two magnetic transitions emerging at ∼24 K and ∼10 K, respectively, corresponding to the antiferromagnetic ordering and canted arrangement of the Eu moments. Our findings shed new light on the intrinsic properties of EuMn0.8Sb2 and demonstrate the existence of Dirac fermions.
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Affiliation(s)
- Qinqing Zhu
- Hangzhou Key Laboratory of Quantum Matter, Department of Physics, Hangzhou Normal University, Hangzhou 310036, People's Republic of China
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4
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Kumar R, Singh S, Nair S. Scaling of magnetotransport in the Ba(Fe 1-x Co x ) 2As 2 series. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:115601. [PMID: 30625446 DOI: 10.1088/1361-648x/aafcff] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present magnetotransport studies of the parent, an underdoped and an optimally doped composition of the Ba(Fe1-x Co x )2As2 series. We observe that both the Kohler's and modified Kohler's scaling is typically violated in these systems. A notable exception is the magnetically ordered state of the underdoped composition where the modified Kohler's scaling is observed to be valid, indicating its relative similarity to the cuprates and some heavy fermion systems. This composition also exhibits a feature in the Hall angle, which could signify the opening of a pseudogap before the onset of long range magnetic order. The implications of our observations are discussed in the context of magnetotransport of metals with incipient magnetic fluctuations.
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Affiliation(s)
- Rohit Kumar
- Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, Maharashtra-411008, India
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5
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Kumar R, Harnagea L, Lakhani A, Nair S. Magnetotransport studies of optimally doped Sr(Fe 1-x Co x ) 2As 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:505601. [PMID: 30460923 DOI: 10.1088/1361-648x/aaeb16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report magnetotransport measurements and their scaling analysis for the optimally electron-doped Sr(Fe0.88Co[Formula: see text]As2 system. We observe that both the Kohler's and modified Kohler's scalings are violated. Interestingly, the Hall angle displays a quadratic temperature dependence (cot[Formula: see text] [Formula: see text] T 2) similar to many cuprates and heavy fermion systems. The fact that this T 2 dependence is seen in spite of the violation of modified Kohler's scaling suggests that the Hall angle and magnetoresistance are not governed by the same scattering mechanism. We also observe a linear magnetoresistance in this system, which does not harbor a spin density wave ground state. Implications of our observations are discussed in the context of existing models for the magnetotransport of these strongly correlated electron systems.
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Affiliation(s)
- Rohit Kumar
- Department of Physics, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune, Maharashtra-411008, India
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6
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Abstract
Using polarized optical and magneto-optical spectroscopy, we have demonstrated universal aspects of electrodynamics associated with Dirac nodal lines that are found in several classes of unconventional intermetallic compounds. We investigated anisotropic electrodynamics of [Formula: see text] where the spin-orbit coupling (SOC) triggers energy gaps along the nodal lines. These gaps manifest as sharp steps in the optical conductivity spectra [Formula: see text] This behavior is followed by the linear power-law scaling of [Formula: see text] at higher frequencies, consistent with our theoretical analysis for dispersive Dirac nodal lines. Magneto-optics data affirm the dominant role of nodal lines in the electrodynamics of [Formula: see text].
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Blomberg EC, Tanatar MA, Thaler A, Bud'ko SL, Canfield PC, Prozorov R. Multi-band effects in in-plane resistivity anisotropy of strain-detwinned disordered Ba(Fe 1-xRu x) 2As 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:315601. [PMID: 29992907 DOI: 10.1088/1361-648x/aacf2e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In-plane resistivity anisotropy was measured in strain-detwinned as-grown and partially annealed samples of isovalently-substituted [Formula: see text] ([Formula: see text]) and the results were contrasted with previous reports on anneal samples with low residual resistivity. In samples with high residual resistivity, detwinned with application of strain, the difference of the two components of in-plane resistivity in the orthorhombic phase, [Formula: see text], was found to obey Matthiessen rule irrespective of sample composition, which is in stark contrast with observations on annealed samples. Our findings are consistent with two-band transport model in which contribution from high mobility carriers of small pockets of the Fermi surface has negligible anisotropy of residual resistivity and is eliminated by disorder. Our finding suggests that magnetic/nematic order has dramatically different effect on different parts of the Fermi surface. It predominantly affects inelastic scattering for small pocket high mobility carriers and elastic impurity scattering for larger sheets of the Fermi surface.
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Affiliation(s)
- E C Blomberg
- Ames Laboratory USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA, United States of America
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8
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Abstract
According to an earlier Abrikosov model, a positive, nonsaturating, linear magnetoresistivity (LMR) is expected in clean, low-carrier-density metals when measured at very low temperatures and under very high magnetic fields. Recently, a vast class of materials were shown to exhibit extraordinary high LMR but at conditions that deviate sharply from the above-mentioned Abrikosov-type conditions. Such deviations are often considered within either classical Parish-Littlewood scenario of random-conductivity network or within a quantum scenario of small-effective mass or low carriers at tiny pockets neighboring the Fermi surface. This work reports on a manifestation of novel example of a robust, but moderate, LMR up to ∼100 K in the diamagnetic, layered, compensated, semimetallic CaAl2Si2. We carried out extensive and systematic characterization of baric and thermal evolution of LMR together with first-principles electronic structure calculations based on density functional theory. Our analyses revealed strong correlations among the main parameters of LMR and, in addition, a presence of various transition/crossover events based on which a P - T phase diagram was constructed. We discuss whether CaAl2Si2 can be classified as a quantum Abrikosov or classical Parish-Littlewood LMR system.
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9
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Xing X, Xu C, Li Z, Feng J, Zhou N, Zhang Y, Sun Y, Zhou W, Xu X, Shi Z. Angular-dependent magnetoresistance study in Ca 0.73La 0.27FeAs 2: a 'parent' compound of 112-type iron pnictide superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:025701. [PMID: 29214979 DOI: 10.1088/1361-648x/aa9c11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report a study of angular-dependent magnetoresistance (AMR) with the magnetic field rotated in the plane perpendicular to the current on a Ca0.73La0.27FeAs2 single crystal, which is regarded as a 'parent' compound of 112-type iron pnictide superconductors. A pronounced AMR with twofold symmetry is observed, signifying the highly anisotropic Fermi surface. By further analyzing the AMR data, we find that the Fermi surface above the structural/antiferromagnetic (AFM) transition (T s/T N) is quasi-two-dimensional (quasi-2D), as revealed by the 2D scaling behavior of the AMR, Δρ/ρ(0) (H, θ) = Δρ/ρ(0) (µ 0 Hcosθ), θ being the magnetic field angle with respect to the c axis. While such 2D scaling becomes invalid at temperatures below T s/T N, the three-dimensional (3D) scaling approach by inclusion of the anisotropy of the Fermi surface is efficient, indicating that the appearance of the 3D Fermi surface contributes to anisotropic electronic transport. Compared with other experimental observations, we suspect that the additional 3D hole pocket (generated by the Ca d orbital and As1 p z orbital) around the Γ point in CaFeAs2 will disappear in the heavily electron doped regime, and moreover, the Fermi surface should be reconstructed across the structural/AFM transition. Besides, a quasi-linear in-plane magnetoresistance with H//ab is observed at low temperatures and its possible origins are also discussed. Our results provide more information to further understand the electronic structure of 112-type IBSs.
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Affiliation(s)
- Xiangzhuo Xing
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, People's Republic of China
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10
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Pan J, Karki A, Plummer EW, Jin R. Doping effect on the physical properties of Ca 10Pt 3As 8(Fe 2As 2) 5 single crystals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:485702. [PMID: 29120865 DOI: 10.1088/1361-648x/aa958f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ca10Pt3As8(Fe2As2)5 is a unique parent compound for superconductivity, which consists of both semiconducting Pt3As8 and metallic FeAs layers. We report the observation of superconductivity induced via chemical doping in either Ca site using rare-earth (RE) elements (RE = La, Gd) or Fe site using Pt. The interlayer distance and the normal-state physical properties of the doped system change correspondingly. The coupled changes include (1) superconducting transition temperature T c increases with increasing both doping concentration and interlayer distance, (2) our T c value is higher than previously reported maximum value for Pt doping in the Fe site, (3) both the normal-state in-plane resistivity and out-of-plane resistivity change from non-metallic to metallic behavior with increasing doping concentration and T c, and (4) the transverse in-plane magnetoresistance (MRab) changes from linear-field dependence to quadratic behavior upon increasing T c. For La-doped compound with the highest T c (~35 K), upper critical fields ([Formula: see text], [Formula: see text]), coherence lengths (ξ ab, ξ c), and in-plane penetration depth (λ ab) are estimated. We discuss the relationship between chemical doping, interlayer distance, and physical properties in this system.
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Affiliation(s)
- Jiayun Pan
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge 70803, United States of America
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11
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Chen ZG, Wang L, Song Y, Lu X, Luo H, Zhang C, Dai P, Yin Z, Haule K, Kotliar G. Two-Dimensional Massless Dirac Fermions in Antiferromagnetic AFe_{2}As_{2} (A=Ba,Sr). PHYSICAL REVIEW LETTERS 2017; 119:096401. [PMID: 28949552 DOI: 10.1103/physrevlett.119.096401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Indexed: 06/07/2023]
Abstract
We report infrared studies of AFe_{2}As_{2} (A=Ba, Sr), two representative parent compounds of iron-arsenide superconductors, at magnetic fields (B) up to 17.5 T. Optical transitions between Landau levels (LLs) were observed in the antiferromagnetic states of these two parent compounds. Our observation of a sqrt[B] dependence of the LL transition energies, the zero-energy intercepts at B=0 T under the linear extrapolations of the transition energies and the energy ratio (∼2.4) between the observed LL transitions, combined with the linear band dispersions in two-dimensional (2D) momentum space obtained by theoretical calculations, demonstrates the existence of massless Dirac fermions in the antiferromagnet BaFe_{2}As_{2}. More importantly, the observed dominance of the zeroth-LL-related absorption features and the calculated bands with extremely weak dispersions along the momentum direction k_{z} indicate that massless Dirac fermions in BaFe_{2}As_{2} are 2D. Furthermore, we find that the total substitution of the barium atoms in BaFe_{2}As_{2} by strontium atoms not only maintains 2D massless Dirac fermions in this system, but also enhances their Fermi velocity, which supports that the Dirac points in iron-arsenide parent compounds are topologically protected.
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Affiliation(s)
- Zhi-Guo Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Luyang Wang
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
- Sate Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yu Song
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Xingye Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huiqian Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chenglin Zhang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Zhiping Yin
- Center of Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Kristjan Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
- DMFT-MatDeLab Center, Upton, New York 11973, USA
| | - Gabriel Kotliar
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
- DMFT-MatDeLab Center, Upton, New York 11973, USA
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12
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Craco L, Leoni S. Selective orbital reconstruction in tetragonal FeS: A density functional dynamical mean-field theory study. Sci Rep 2017; 7:46439. [PMID: 28418042 PMCID: PMC5394419 DOI: 10.1038/srep46439] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/17/2017] [Indexed: 11/11/2022] Open
Abstract
Transport properties of tetragonal iron monosulfide, mackinawite, show a range of complex features. Semiconductive behavior and proximity to metallic states with nodal superconductivity mark this d-band system as unconventional quantum material. Here, we use the density functional dynamical mean-field theory (DFDMFT) scheme to comprehensively explain why tetragonal FeS shows both semiconducting and metallic responses in contrast to tetragonal FeSe which is a pseudogaped metal above the superconducting transition temperature. Within local-density-approximation plus dynamical mean-field theory (LDA+DMFT) we characterize its paramagnetic insulating and metallic phases, showing the proximity of mackinawite to selective Mott localization. We report the coexistence of pseudogaped and anisotropic Dirac-like electronic dispersion at the border of the Mott transition. These findings announce a new understanding of many-particle physics in quantum materials with coexisting Dirac-fermions and pseudogaped electronic states at low energies. Based on our results we propose that in electron-doped FeS substantial changes would be seen when the metallic regime was tuned towards an electronic state that hosts unconventional superconductivity.
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Affiliation(s)
- Luis Craco
- Instituto de Física, Universidade Federal de Mato Grosso, Cuiabá, MT, 78060-900, Brazil
| | - Stefano Leoni
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
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13
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Large nonsaturating magnetoresistance and signature of nondegenerate Dirac nodes in ZrSiS. Proc Natl Acad Sci U S A 2017; 114:2468-2473. [PMID: 28223488 DOI: 10.1073/pnas.1618004114] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Whereas the discovery of Dirac- and Weyl-type excitations in electronic systems is a major breakthrough in recent condensed matter physics, finding appropriate materials for fundamental physics and technological applications is an experimental challenge. In all of the reported materials, linear dispersion survives only up to a few hundred millielectronvolts from the Dirac or Weyl nodes. On the other hand, real materials are subject to uncontrolled doping during preparation and thermal effect near room temperature can hinder the rich physics. In ZrSiS, angle-resolved photoemission spectroscopy measurements have shown an unusually robust linear dispersion (up to [Formula: see text]2 eV) with multiple nondegenerate Dirac nodes. In this context, we present the magnetotransport study on ZrSiS crystal, which represents a large family of materials (WHM with W = Zr, Hf; H = Si, Ge, Sn; M = O, S, Se, Te) with identical band topology. Along with extremely large and nonsaturating magnetoresistance (MR), [Formula: see text]1.4 [Formula: see text] 105% at 2 K and 9 T, it shows strong anisotropy, depending on the direction of the magnetic field. Quantum oscillation and Hall effect measurements have revealed large hole and small electron Fermi pockets. A nontrivial [Formula: see text] Berry phase confirms the Dirac fermionic nature for both types of charge carriers. The long-sought relativistic phenomenon of massless Dirac fermions, known as the Adler-Bell-Jackiw chiral anomaly, has also been observed.
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14
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Wang LX, Wang S, Li JG, Li CZ, Xu J, Yu D, Liao ZM. Magnetotransport properties near the Dirac point of Dirac semimetal Cd 3As 2 nanowires. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:044003. [PMID: 27897146 DOI: 10.1088/1361-648x/29/4/044003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Three-dimensional (3D) Dirac semimetals are featured by 3D linear energy-momentum dispersion relation, which have been proposed to be a desirable system to study Dirac fermions in 3D space and Weyl fermions in solid-state materials. Significantly, to reveal exotic transport properties of Dirac semimetals, the Fermi level should be close to the Dirac point, around which the linear dispersion is retained. Here we report the magnetotransport properties near the Dirac point in Cd3As2 nanowires, manifesting the evolution of band structure under magnetic field. Ambipolar field effect is observed with the Dirac point at V g = 3.9 V. Under high magnetic field, there is a resistivity dip in transfer curve at the Dirac point, which is caused by the Zeeman splitting enhanced density of state around the Dirac point. Furthermore, the low carrier density in the nanowires makes it feasible to enter into the quantum limit regime, resulting in the quantum linear magnetoresistance being observed even at room temperature. Besides, the dramatic reduction of bulk conductivity due to the low carrier density, together with a large surface to volume ratio of the nanowire, collectively help to reveal the Shubnikov-de Haas oscillations from the surface states. Our studies on transport properties around the Dirac point therefore provide deep insights into the emerging exotic physics of Dirac and Weyl fermions.
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Affiliation(s)
- Li-Xian Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
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15
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Tanatar MA, Böhmer AE, Timmons EI, Schütt M, Drachuck G, Taufour V, Kothapalli K, Kreyssig A, Bud'ko SL, Canfield PC, Fernandes RM, Prozorov R. Origin of the Resistivity Anisotropy in the Nematic Phase of FeSe. PHYSICAL REVIEW LETTERS 2016; 117:127001. [PMID: 27689292 DOI: 10.1103/physrevlett.117.127001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Indexed: 06/06/2023]
Abstract
The in-plane resistivity anisotropy is studied in strain-detwinned single crystals of FeSe. In contrast to other iron-based superconductors, FeSe does not develop long-range magnetic order below the tetragonal-to-orthorhombic transition at T_{s}≈90 K. This allows for the disentanglement of the contributions to the resistivity anisotropy due to nematic and magnetic orders. Comparing direct transport and elastoresistivity measurements, we extract the intrinsic resistivity anisotropy of strain-free samples. The anisotropy peaks slightly below T_{s} and decreases to nearly zero on cooling down to the superconducting transition. This behavior is consistent with a scenario in which the in-plane resistivity anisotropy is dominated by inelastic scattering by anisotropic spin fluctuations.
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Affiliation(s)
- M A Tanatar
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | | | - E I Timmons
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - M Schütt
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - G Drachuck
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - V Taufour
- Ames Laboratory, Ames, Iowa 50011, USA
| | - K Kothapalli
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A Kreyssig
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - S L Bud'ko
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - P C Canfield
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - R Prozorov
- Ames Laboratory, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
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16
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Fei F, Wei Z, Wang Q, Lu P, Wang S, Qin Y, Pan D, Zhao B, Wang X, Sun J, Wang X, Wang P, Wan J, Zhou J, Han M, Song F, Wang B, Wang G. Solvothermal Synthesis of Lateral Heterojunction Sb2Te3/Bi2Te3 Nanoplates. NANO LETTERS 2015; 15:5905-5911. [PMID: 26305696 DOI: 10.1021/acs.nanolett.5b01987] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A lateral heterojunction of topological insulator Sb2Te3/Bi2Te3 was successfully synthesized using a two-step solvothermal method. The two crystalline components were separated well by a sharp lattice-matched interface when the optimized procedure was used. Inspecting the heterojunction using high-resolution transmission electron microscopy showed that epitaxial growth occurred along the horizontal plane. The semiconducting temperature-resistance curve and crossjunction rectification were observed, which reveal a staggered-gap lateral heterojunction with a small junction voltage. Quantum correction from the weak antilocalization reveals the well-maintained transport of the topological surface state. This is appealing for a platform for spin filters and one-dimensional topological interface states.
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Affiliation(s)
- Fucong Fei
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Zhongxia Wei
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Qianjin Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Material Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Pengchao Lu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Shuangbao Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Material Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Yuyuan Qin
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Danfeng Pan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Bo Zhao
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Xuefeng Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and School of Electronic Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Jian Sun
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Xinran Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and School of Electronic Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Peng Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Material Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Jianguo Wan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Jianfeng Zhou
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Material Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Min Han
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and School of Electronic Science and Engineering, Nanjing University , Nanjing 210093, P. R. China
| | - Fengqi Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Baigeng Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
| | - Guanghou Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University , Nanjing 210093, P. R. China
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17
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Aitani M, Hirahara T, Ichinokura S, Hanaduka M, Shin D, Hasegawa S. In situ magnetotransport measurements in ultrathin Bi films: evidence for surface-bulk coherent transport. PHYSICAL REVIEW LETTERS 2014; 113:206802. [PMID: 25432051 DOI: 10.1103/physrevlett.113.206802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 06/04/2023]
Abstract
We performed in situ magnetotransport measurements on ultrathin Bi(111) films [4-30 bilayers (BLs), 16-120 Å thick] to elucidate the role of bulk or surface states in the transport phenomena. We found that the temperature dependence of the film conductivity shows no thickness dependence for the 6-16 BL films and is affected by the electron-electron scattering, suggesting surface-state dominant contribution. In contrast, the weak antilocalization effect observed by applying a magnetic field shows clear thickness dependence, indicating bulk transport. This apparent inconsistency is explained by a coherent bulk-surface coupling that produces a single channel transport. For the films thicker than 20 BLs, the behavior changes drastically which can likely be interpreted as a bulk dominant conduction.
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Affiliation(s)
- Masaki Aitani
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Toru Hirahara
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Satoru Ichinokura
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahiro Hanaduka
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Dongyoon Shin
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shuji Hasegawa
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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18
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Terashima T, Kurita N, Tomita M, Kihou K, Lee CH, Tomioka Y, Ito T, Iyo A, Eisaki H, Liang T, Nakajima M, Ishida S, Uchida SI, Harima H, Uji S. Complete Fermi surface in BaFe2As2 observed via Shubnikov-de Haas oscillation measurements on detwinned single crystals. PHYSICAL REVIEW LETTERS 2011; 107:176402. [PMID: 22107545 DOI: 10.1103/physrevlett.107.176402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Indexed: 05/31/2023]
Abstract
We show that the Fermi surface (FS) in the antiferromagnetic phase of BaFe(2)As(2) is composed of one hole and two electron pockets, all of which are three dimensional and closed, in sharp contrast to the FS observed by angle-resolved photoemission spectroscopy. Considerations on the carrier compensation and Sommerfeld coefficient rule out existence of unobserved FS pockets of significant sizes. A standard band structure calculation reasonably accounts for the observed FS, despite the overestimated ordered moment. The mass enhancement, the ratio of the effective mass to the band mass, is 2-3.
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Affiliation(s)
- Taichi Terashima
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0003, Japan
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