1
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Xu X, Hao Y, Peng S, Zhang Q, Ni D, Yang C, Dai X, Cao H, Cava RJ. Large off-diagonal magnetoelectricity in a triangular Co 2+-based collinear antiferromagnet. Nat Commun 2023; 14:8034. [PMID: 38052828 DOI: 10.1038/s41467-023-43858-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 11/22/2023] [Indexed: 12/07/2023] Open
Abstract
Magnetic toroidicity is an uncommon type of magnetic structure in solid-state materials. Here, we experimentally demonstrate that collinear spins in a material with R-3 lattice symmetry can host a significant magnetic toroidicity, even parallel to the ordered spins. Taking advantage of a single crystal sample of CoTe6O13 with an R-3 space group and a Co2+ triangular sublattice, temperature-dependent magnetic, thermodynamic, and neutron diffraction results reveal A-type antiferromagnetic order below 19.5 K, with magnetic point group -3' and k = (0,0,0). Our symmetry analysis suggests that the missing mirror symmetry in the lattice could lead to the local spin canting for a toroidal moment along the c axis. Experimentally, we observe a large off-diagonal magnetoelectric coefficient of 41.2 ps/m that evidences the magnetic toroidicity. In addition, the paramagnetic state exhibits a large effective moment per Co2+, indicating that the magnetic moment in CoTe6O13 has a significant orbital contribution. CoTe6O13 embodies an excellent opportunity for the study of next-generation functional magnetoelectric materials.
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Affiliation(s)
- Xianghan Xu
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
| | - Yiqing Hao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Shiyu Peng
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Qiang Zhang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Danrui Ni
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Chen Yang
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Xi Dai
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Huibo Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
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2
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Zhang X, Xu Y, Halloran T, Zhong R, Broholm C, Cava RJ, Drichko N, Armitage NP. A magnetic continuum in the cobalt-based honeycomb magnet BaCo 2(AsO 4) 2. Nat Mater 2023; 22:58-63. [PMID: 36411349 DOI: 10.1038/s41563-022-01403-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Quantum spin liquids (QSLs) are topologically ordered states of matter that host fractionalized excitations. A particular route towards a QSL is via strongly bond-dependent interactions on the hexagonal lattice. A number of Ru- and Ir-based candidate Kitaev QSL materials have been pursued, but all have appreciable non-Kitaev interactions. Using time-domain terahertz spectroscopy, we observed a broad magnetic continuum over a wide range of temperatures and fields in the honeycomb cobalt-based magnet BaCo2(AsO4)2, which has been proposed to be a more ideal version of a Kitaev QSL. Applying an in-plane magnetic field of ~0.5 T suppresses the magnetic order, and at higher fields, applying the field gives rise to a spin-polarized state. Under a 4 T magnetic field that was oriented principally out of plane, a broad magnetic continuum was observed that may be consistent with a field-induced QSL. Our results indicate BaCo2(AsO4)2 is a promising QSL candidate.
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Affiliation(s)
- Xinshu Zhang
- Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - Yuanyuan Xu
- Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - T Halloran
- Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - Ruidan Zhong
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - C Broholm
- Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - N Drichko
- Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - N P Armitage
- Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA.
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada.
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3
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Guo S, Mitchell Warden HE, Cava RJ. Structural Diversity in Oxoiridates with 1D Ir nO 3(n+1) Chain Fragments and Flat Bands. Inorg Chem 2022; 61:10043-10050. [PMID: 35709355 DOI: 10.1021/acs.inorgchem.2c00957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A previously unreported series of hexagonal-perovskite-based Rb-oxoiridates, Rb5Ir2O9, Rb7Ir3O12, and Rb12Ir7O24, have been synthesized and structurally analyzed via N2-protected single-crystal X-ray diffraction (SC-XRD). These materials exhibit different 1D IrnO3(n+1) chain fragments along their c axes. IrO6 octahedra and RbOx (x = 6, 8, and 10) polyhedra are their basic building blocks. The IrO6 octahedra are linked via face-sharing, forming Ir2O9 dimers, Ir3O12 trimers, and Ir7O24 heptamers. The nonmagnetic RbOx (x = 6, 8, and 10) polyhedra serve as both bridging units and spacers. Temperature-dependent SC-XRD shows all three to display positive thermal expansion and rules out structural transitions from their triangular symmetries down to 100 K. Density functional theory results suggest semiconducting-like behavior for the title compounds. The flatness of the electronic bands and our structural analysis are of potential interest for understanding and designing 1D quantum materials.
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Affiliation(s)
- Shu Guo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | | | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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4
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Idzuchi H, Pientka F, Huang KF, Harada K, Gül Ö, Shin YJ, Nguyen LT, Jo NH, Shindo D, Cava RJ, Canfield PC, Kim P. Unconventional supercurrent phase in Ising superconductor Josephson junction with atomically thin magnetic insulator. Nat Commun 2021; 12:5332. [PMID: 34504077 PMCID: PMC8429564 DOI: 10.1038/s41467-021-25608-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 08/22/2021] [Indexed: 11/23/2022] Open
Abstract
In two-dimensional (2D) NbSe2 crystal, which lacks inversion symmetry, strong spin-orbit coupling aligns the spins of Cooper pairs to the orbital valleys, forming Ising Cooper pairs (ICPs). The unusual spin texture of ICPs can be further modulated by introducing magnetic exchange. Here, we report unconventional supercurrent phase in van der Waals heterostructure Josephson junctions (JJs) that couples NbSe2 ICPs across an atomically thin magnetic insulator (MI) Cr2Ge2Te6. By constructing a superconducting quantum interference device (SQUID), we measure the phase of the transferred Cooper pairs in the MI JJ. We demonstrate a doubly degenerate nontrivial JJ phase (ϕ), formed by momentum-conserving tunneling of ICPs across magnetic domains in the barrier. The doubly degenerate ground states in MI JJs provide a two-level quantum system that can be utilized as a new dissipationless component for superconducting quantum devices. Our work boosts the study of various superconducting states with spin-orbit coupling, opening up an avenue to designing new superconducting phase-controlled quantum electronic devices. Van der Waals structures provide a new platform to explore novel physics of superconductor/ferromagnet interfaces. Here, NbSe2 Josephson junction with Cr2Ge2Te6 enables non-trivial Josephson phase by spin-dependent interaction, boosting the study of superconducting states with spin-orbit coupling and phase-controlled quantum electronic device.
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Affiliation(s)
- H Idzuchi
- Department of Physics, Harvard University, Cambridge, MA, USA.,WPI Advanced Institute for Materials Research and Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
| | - F Pientka
- Department of Physics, Harvard University, Cambridge, MA, USA.,Institut für Theoretische Physik, Goethe-Universität, Frankfurt am Main, Germany
| | - K-F Huang
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - K Harada
- Center for Emergent Matter Science (CEMS), RIKEN, Hatoyama, Saitama, Japan
| | - Ö Gül
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Y J Shin
- Department of Physics, Harvard University, Cambridge, MA, USA.,Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA
| | - L T Nguyen
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - N H Jo
- Department of Physics and Astronomy, Iowa State University, Ames, IA, USA.,Ames Laboratory, Iowa State University, Ames, IA, USA
| | - D Shindo
- Center for Emergent Matter Science (CEMS), RIKEN, Hatoyama, Saitama, Japan
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - P C Canfield
- Department of Physics and Astronomy, Iowa State University, Ames, IA, USA.,Ames Laboratory, Iowa State University, Ames, IA, USA
| | - P Kim
- Department of Physics, Harvard University, Cambridge, MA, USA.
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5
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Teknowijoyo S, Cho K, Timmons EI, Tanatar MA, Krizan JW, Cava RJ, Prozorov R. Low-temperature high-frequency dynamic magnetic susceptibility of classical spin-ice Dy 2Ti 2O 7. J Phys Condens Matter 2021; 33:455802. [PMID: 34380114 DOI: 10.1088/1361-648x/ac1cb0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Radio-frequency (14.6 MHz) AC magnetic susceptibility,χAC', of Dy2Ti2O7was measured using self-oscillating tunnel-diode resonator. Measurements were made with the excitation AC field parallel to the superimposed DC magnetic field up to 5 T in a wide temperature range from 50 mK to 100 K. At 14.6 MHz, a known broad peak ofχAC'(T)from kHz-range audio-frequency measurements around 15 K for both [111] and [110] directions shifts to 45 K, continuing the Arrhenius activated behavior with the same activation energy barrier ofEa≈ 230 K. Magnetic field dependence ofχAC'along [111] reproduces previously reported low-temperature two-in-two-out to three-in-one-out spin configuration transition at about 1 T, and an intermediate phase between 1 and 1.5 T. The boundaries of the intermediate phase show reasonable overlap with the literature data and connect at a critical endpoint of the first order transition line, suggesting that these features are frequency independent. An unusual upturn of the magnetic susceptibility atT→ 0 was observed in magnetic fields between 1.5 T and 2 T for both magnetic field directions, before fully polarized configuration sets in above 2 T.
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Affiliation(s)
- S Teknowijoyo
- Ames Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| | - K Cho
- Ames Laboratory, Ames, IA 50011, United States of America
| | - E I Timmons
- Ames Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| | - M A Tanatar
- Ames Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| | - J W Krizan
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States of America
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States of America
| | - R Prozorov
- Ames Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
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6
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Kazim S, Alì M, Palleschi S, D'Olimpio G, Mastrippolito D, Politano A, Gunnella R, Di Cicco A, Renzelli M, Moccia G, Cacioppo OA, Alfonsetti R, Strychalska-Nowak J, Klimczuk T, J Cava R, Ottaviano L. Mechanical exfoliation and layer number identification of single crystal monoclinic CrCl 3. Nanotechnology 2020; 31:395706. [PMID: 32150734 DOI: 10.1088/1361-6528/ab7de6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
After the recent finding that CrI3, displays ferromagnetic order down to its monolayer, extensive studies have followed to pursue new two-dimensional (2D) magnetic materials. In this article, we report on the growth of single crystal CrCl3 in the layered monoclinic phase. The system after mechanical exfoliation exhibits stability in ambient air (the degradation occurs on a time scale at least four orders of magnitude longer than is observed for CrI3). By means of mechanical cleavage and atomic force microscopy (AFM) combined with optical identification, we demonstrate the systematic isolation of single and few layer flakes onto 270 nm and 285 nm SiO2/Si (100) substrates with lateral size larger than graphene flakes isolated with the same method. The layer number identification has been carried with statistically significant data, quantifying the optical contrast as a function of the number of layers for up to six layers. Layer dependent optical contrast data have been fitted within the Fresnel equation formalism determining the real and imaginary part of the wavelength dependent refractive index of the material. A layer dependent (532 nm) micro-Raman study has been carried out down to two layers with no detectable spectral shifts as a function of the layer number and with respect to the bulk.
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Affiliation(s)
- S Kazim
- School of Science and Technology Physics division, Università di Camerino, Italy
| | - M Alì
- Department of Physical and Chemical Sciences (DSFC) Università dell'Aquila, L'Aquila, Italy
| | - S Palleschi
- Department of Physical and Chemical Sciences (DSFC) Università dell'Aquila, L'Aquila, Italy
- Lfoundry, Avezzano (AQ), Italy
| | - G D'Olimpio
- Department of Physical and Chemical Sciences (DSFC) Università dell'Aquila, L'Aquila, Italy
| | - D Mastrippolito
- Department of Physical and Chemical Sciences (DSFC) Università dell'Aquila, L'Aquila, Italy
| | - A Politano
- Department of Physical and Chemical Sciences (DSFC) Università dell'Aquila, L'Aquila, Italy
| | - R Gunnella
- School of Science and Technology Physics division, Università di Camerino, Italy
| | - A Di Cicco
- School of Science and Technology Physics division, Università di Camerino, Italy
| | | | | | | | | | - J Strychalska-Nowak
- Faculty of Applied Physics and Mathematics Gdansk University of Technology, Gdansk, Poland
| | - T Klimczuk
- Faculty of Applied Physics and Mathematics Gdansk University of Technology, Gdansk, Poland
| | - R J Cava
- Department of Chemistry Princeton University, Princeton, NJ 08544, United States of America
| | - L Ottaviano
- Department of Physical and Chemical Sciences (DSFC) Università dell'Aquila, L'Aquila, Italy
- CNR-SPIN uos L'Aquila, L'Aquila Italy
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7
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Affiliation(s)
- Loi T. Nguyen
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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8
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Abstract
KIrO3 in the body-centered cubic variant of the KSbO3-type structure is reported. Black cube-shaped single crystals, obtained from the solid-state reaction in a half-closed silver capsule in a sealed quartz tube, were used for the structural characterization by single-crystal X-ray diffraction. The material, space group Im3[combining macron] (no. 204), exhibits a disordered K array and a three-dimensional (3D) IrO6-based tunnel-like framework. Temperature-dependent magnetization and heat capacity measurements suggest a paramagnetic state for KIrO3, with significant contribution of temperature independent paramagnetism and without any sign of long-range magnetic ordering (down to 1.8 K). The 3D motif of this material, based on the 5d Ir5+ ion, is of interest for investigating unconventional magnetism.
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Affiliation(s)
- Shu Guo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
| | - Kelly M Powderly
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
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9
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Wang W, Kim S, Liu M, Cevallos FA, Cava RJ, Ong NP. Evidence for an edge supercurrent in the Weyl superconductor MoTe2. Science 2020; 368:534-537. [DOI: 10.1126/science.aaw9270] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 08/22/2019] [Accepted: 03/27/2020] [Indexed: 11/02/2022]
Abstract
Edge supercurrents in superconductors have long been an elusive target. Interest in them has reappeared in the context of topological superconductivity. We report evidence for the existence of a robust edge supercurrent in the Weyl superconductor molybdenum ditelluride (MoTe2). In a magnetic field B, fluxoid quantization generates a periodic modulation of the edge condensate observable as a “fast-mode” oscillation of the critical current Ic versus B. The fast-mode frequency is distinct from the conventional Fraunhofer oscillation displayed by the bulk supercurrent. We confirm that the fast-mode frequency increases with crystal area as expected for an edge supercurrent. In addition, weak excitation branches are resolved that display an unusual broken symmetry.
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Affiliation(s)
- Wudi Wang
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Stephan Kim
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Minhao Liu
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - F. A. Cevallos
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - N. P. Ong
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
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10
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Górnicka K, Gutowska S, Winiarski MJ, Wiendlocha B, Xie W, Cava RJ, Klimczuk T. Superconductivity on a Bi Square Net in LiBi. Chem Mater 2020; 32:3150-3159. [PMID: 33122877 PMCID: PMC7588065 DOI: 10.1021/acs.chemmater.0c00179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/15/2020] [Indexed: 06/11/2023]
Abstract
We present the crystallographic analysis, superconducting characterization and theoretical modeling of LiBi, that contains the lightest and the heaviest nonradioactive metal. The compound crystallizes in a tetragonal (CuAu-type) crystal structure with Bi square nets separated by Li planes (parameters a = 3.3636(1) Å and c = 4.2459(2) Å, c/a = 1.26). Superconducting state was studied in detail by magnetic susceptibility and heat capacity measurements. The results reveal that LiBi is a moderately coupled type-I superconductor (λe-p = 0.66) with T c = 2.48 K and a thermodynamic critical field Hc(0) = 157 Oe. Theoretical studies show that bismuth square net is responsible for superconductivity in this compound, but the coupling between the Li planes and Bi planes makes a significant contribution to the superconductivity.
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Affiliation(s)
- Karolina Górnicka
- Faculty
of Applied Physics and Mathematics, Gdansk
University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland
- Advanced
Materials Centre, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Sylwia Gutowska
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059 Kraków, Poland
| | - Michał J. Winiarski
- Faculty
of Applied Physics and Mathematics, Gdansk
University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland
- Advanced
Materials Centre, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Bartlomiej Wiendlocha
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059 Kraków, Poland
| | - Weiwei Xie
- Department
of Chemistry, Louisiana State University, Baton Rouge Louisiana 70803, United States
| | - R. J. Cava
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Tomasz Klimczuk
- Faculty
of Applied Physics and Mathematics, Gdansk
University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland
- Advanced
Materials Centre, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland
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11
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Guo S, Zhong R, Wang W, Tao J, Ni D, Cava RJ. K3Ir2O6 and K16.3Ir8O30, Low-Dimensional Iridates with Infinite IrO6 Chains. J Am Chem Soc 2020; 142:5389-5395. [DOI: 10.1021/jacs.0c00849] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shu Guo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Ruidan Zhong
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Wei Wang
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jing Tao
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Danrui Ni
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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12
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Affiliation(s)
- C. Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - S. A. Kivelson
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - D. G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - M. R. Norman
- Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - T. Senthil
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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13
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Liang S, Kushwaha S, Gao T, Hirschberger M, Li J, Wang Z, Stolze K, Skinner B, Bernevig BA, Cava RJ, Ong NP. A gap-protected zero-Hall effect state in the quantum limit of the non-symmorphic metal KHgSb. Nat Mater 2019; 18:443-447. [PMID: 30833782 DOI: 10.1038/s41563-019-0303-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/30/2019] [Indexed: 06/09/2023]
Abstract
A recurring theme in topological matter is the protection of unusual electronic states by symmetry, for example, protection of the surface states in Z2 topological insulators by time-reversal symmetry1-3. Recently, interest has turned to unusual surface states in the large class of non-symmorphic materials4-12. In particular, KHgSb is predicted to exhibit double quantum spin Hall states10. Here we report measurements of the Hall conductivity in KHgSb in a strong magnetic field B. In the quantum limit, the Hall conductivity is observed to fall exponentially to zero, but the diagonal conductivity is finite. A large gap protects this unusual zero-Hall state. We theoretically propose that, in this quantum limit, the chemical potential drops into the bulk gap, intersecting equal numbers of right- and left-moving quantum spin Hall surface modes to produce the zero-Hall state. The zero-Hall state illustrates how topological protection in a non-symmorphic material with glide symmetry may lead to highly unusual transport phenomena.
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Affiliation(s)
- Sihang Liang
- Department of Physics, Princeton University, Princeton, NJ, USA
| | - Satya Kushwaha
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Tong Gao
- Department of Physics, Princeton University, Princeton, NJ, USA
| | | | - Jian Li
- Department of Physics, Princeton University, Princeton, NJ, USA
- School of Science, Westlake University, Hangzhou, China
| | - Zhijun Wang
- Department of Physics, Princeton University, Princeton, NJ, USA
| | - Karoline Stolze
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Brian Skinner
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - B A Bernevig
- Department of Physics, Princeton University, Princeton, NJ, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, NJ, USA.
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14
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Guo S, Kong T, Xie W, Nguyen L, Stolze K, Cevallos FA, Cava RJ. Triangular Rare-Earth Lattice Materials RbBaR(BO3)2 (R = Y, Gd–Yb) and Comparison to the KBaR(BO3)2 Analogs. Inorg Chem 2019; 58:3308-3315. [DOI: 10.1021/acs.inorgchem.8b03372] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shu Guo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Tai Kong
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Weiwei Xie
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Loi Nguyen
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Karoline Stolze
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - F. Alex Cevallos
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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15
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Randeria MT, Agarwal K, Feldman BE, Ding H, Ji H, Cava RJ, Sondhi SL, Parameswaran SA, Yazdani A. Interacting multi-channel topological boundary modes in a quantum Hall valley system. Nature 2019; 566:363-367. [PMID: 30728501 DOI: 10.1038/s41586-019-0913-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/23/2018] [Indexed: 11/09/2022]
Abstract
Symmetry and topology are central to understanding quantum Hall ferromagnets (QHFMs), two-dimensional electronic phases with spontaneously broken spin or pseudospin symmetry whose wavefunctions also have topological properties1,2. Domain walls between distinct broken-symmetry QHFM phases are predicted to host gapless one-dimensional modes-that is, quantum channels that emerge because of a topological change in the underlying electronic wavefunctions at such interfaces. Although various QHFMs have been identified in different materials3-8, interacting electronic modes at these domain walls have not been probed. Here we use a scanning tunnelling microscope to directly visualize the spontaneous formation of boundary modes at domain walls between QHFM phases with different valley polarization (that is, the occupation of equal-energy but quantum mechanically distinct valleys in the electronic structure) on the surface of bismuth. Spectroscopy shows that these modes occur within a topological energy gap, which closes and reopens as the valley polarization switches across the domain wall. By changing the valley flavour and the number of modes at the domain wall, we can realize different regimes in which the valley-polarized channels are either metallic or develop a spectroscopic gap. This behaviour is a consequence of Coulomb interactions constrained by the valley flavour, which determines whether electrons in the topological modes can backscatter, making these channels a unique class of interacting one-dimensional quantum wires. QHFM domain walls can be realized in different classes of two-dimensional materials, providing the opportunity to explore a rich phase space of interactions in these quantum wires.
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Affiliation(s)
- Mallika T Randeria
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA
| | - Kartiek Agarwal
- Department of Electrical Engineering, Princeton University, Princeton, NJ, USA
| | - Benjamin E Feldman
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA.,Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA.,Department of Physics, Stanford University, Stanford, CA, USA
| | - Hao Ding
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA
| | - Huiwen Ji
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - S L Sondhi
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA
| | | | - Ali Yazdani
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA.
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16
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Scheie A, Dasgupta S, Sanders M, Sakai A, Matsumoto Y, Prisk TR, Nakatsuji S, Cava RJ, Broholm C. Homogeneous reduced moment in a gapful scalar chiral kagome antiferromagnet. Phys Rev B 2019; 100:10.1103/physrevb.100.024414. [PMID: 38617197 PMCID: PMC11015473 DOI: 10.1103/physrevb.100.024414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
We present a quantitative experimental investigation of the scalar chiral magnetic order with in Nd3Sb3Mg2O14. Static magnetization reveals a net ferromagnetic ground state, and inelastic neutron scattering from the hyperfine coupled nuclear spin reveals a local ordered moment of 1.76(6) μ B , just 61(2)% of the saturated moment size. The experiments exclude static disorder as the source of the reduced moment. A 38(1) μ eV gap in the magnetic excitation spectrum inferred from heat capacity rules out thermal fluctuations and suggests a multipolar explanation for the moment reduction. We compare Nd3Sb3Mg2O14 to Nd pyrochlores and show that Nd2Zr2O7 is in a spin fragmented state using nuclear Schottky heat capacity.
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Affiliation(s)
- A Scheie
- Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218
| | - S Dasgupta
- Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218
| | - M Sanders
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - A Sakai
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Y Matsumoto
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T R Prisk
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
| | - S Nakatsuji
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - C Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218
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17
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Cai Y, Wilson MN, Hallas AM, Liu L, Frandsen BA, Dunsiger SR, Krizan JW, Cava RJ, Rubel O, Uemura YJ, Luke GM. μSR study of spin freezing and persistent spin dynamics in NaCaNi 2F 7. J Phys Condens Matter 2018; 30:385802. [PMID: 30089706 DOI: 10.1088/1361-648x/aad91c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A new pyrochlore compound, NaCaNi2F7, was recently synthesized and has a single magnetic site with spin-1 Ni2+ . We present zero field and longitudinal field muon spin rotation (μSR) measurements on this pyrochlore. Density functional theory calculations show that the most likely muon site is located between two fluorine ions, but off-centre. A characteristic F-μ-F muon spin polarization function is observed at high temperatures where Ni spin fluctuations are sufficiently rapid. The Ni2+ spins undergo spin freezing into a disordered ground state below 4 K, with a characteristic internal field strength of 140 G. Persistent Ni spin dynamics are present to our lowest temperatures (75 mK), a feature characteristic of many geometrically frustrated magnetic systems.
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Affiliation(s)
- Y Cai
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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18
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Pletikosić I, von Rohr F, Pervan P, Das PK, Vobornik I, Cava RJ, Valla T. Band Structure of the IV-VI Black Phosphorus Analog and Thermoelectric SnSe. Phys Rev Lett 2018; 120:156403. [PMID: 29756873 DOI: 10.1103/physrevlett.120.156403] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/29/2017] [Indexed: 06/08/2023]
Abstract
The success of black phosphorus in fast electronic and photonic devices is hindered by its rapid degradation in the presence of oxygen. Orthorhombic tin selenide is a representative of group IV-VI binary compounds that are robust and isoelectronic and share the same structure with black phosphorus. We measure the band structure of SnSe and find highly anisotropic valence bands that form several valleys having fast dispersion within the layers and negligible dispersion across. This is exactly the band structure desired for efficient thermoelectric generation where SnSe has shown great promise.
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Affiliation(s)
- I Pletikosić
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Condensed Matter and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - F von Rohr
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - P Pervan
- Institut za fiziku, HR-10000 Zagreb, Croatia
| | - P K Das
- Istituto Officina dei Materiali (IOM-CNR), Laboratorio TASC, I-34149 Trieste, Italy
- International Centre for Theoretical Physics, I-34151 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM-CNR), Laboratorio TASC, I-34149 Trieste, Italy
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - T Valla
- Condensed Matter and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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19
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Di Sante D, Das PK, Bigi C, Ergönenc Z, Gürtler N, Krieger JA, Schmitt T, Ali MN, Rossi G, Thomale R, Franchini C, Picozzi S, Fujii J, Strocov VN, Sangiovanni G, Vobornik I, Cava RJ, Panaccione G. Three-Dimensional Electronic Structure of the Type-II Weyl Semimetal WTe_{2}. Phys Rev Lett 2017; 119:026403. [PMID: 28753342 DOI: 10.1103/physrevlett.119.026403] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Indexed: 06/07/2023]
Abstract
By combining bulk sensitive soft-x-ray angular-resolved photoemission spectroscopy and first-principles calculations we explored the bulk electron states of WTe_{2}, a candidate type-II Weyl semimetal featuring a large nonsaturating magnetoresistance. Despite the layered geometry suggesting a two-dimensional electronic structure, we directly observe a three-dimensional electronic dispersion. We report a band dispersion in the reciprocal direction perpendicular to the layers, implying that electrons can also travel coherently when crossing from one layer to the other. The measured Fermi surface is characterized by two well-separated electron and hole pockets at either side of the Γ point, differently from previous more surface sensitive angle-resolved photoemission spectroscopy experiments that additionally found a pronounced quasiparticle weight at the zone center. Moreover, we observe a significant sensitivity of the bulk electronic structure of WTe_{2} around the Fermi level to electronic correlations and renormalizations due to self-energy effects, previously neglected in first-principles descriptions.
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Affiliation(s)
- Domenico Di Sante
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - Pranab Kumar Das
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
- International Centre for Theoretical Physics (ICTP), Strada Costiera 11, I-34100 Trieste, Italy
| | - C Bigi
- Dipartimento di Fisica, Universitá di Milano, Via Celoria 16, I-20133 Milano, Italy
| | - Z Ergönenc
- Computational Materials Physics, University of Vienna, Sensengasse 8/8, A-1090 Vienna, Austria
| | - N Gürtler
- Computational Materials Physics, University of Vienna, Sensengasse 8/8, A-1090 Vienna, Austria
| | - J A Krieger
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
- Laboratorium für Festkörperphysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - T Schmitt
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen, Switzerland
| | - M N Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - G Rossi
- Dipartimento di Fisica, Universitá di Milano, Via Celoria 16, I-20133 Milano, Italy
| | - R Thomale
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - C Franchini
- Computational Materials Physics, University of Vienna, Sensengasse 8/8, A-1090 Vienna, Austria
| | - S Picozzi
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, L'Aquila 67100, Italy
| | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - V N Strocov
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen, Switzerland
| | - G Sangiovanni
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - G Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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20
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Liang T, Lin J, Gibson Q, Gao T, Hirschberger M, Liu M, Cava RJ, Ong NP. Anomalous Nernst Effect in the Dirac Semimetal Cd_{3}As_{2}. Phys Rev Lett 2017; 118:136601. [PMID: 28409962 DOI: 10.1103/physrevlett.118.136601] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Indexed: 06/07/2023]
Abstract
Dirac and Weyl semimetals display a host of novel properties. In Cd_{3}As_{2}, the Dirac nodes lead to a protection mechanism that strongly suppresses backscattering in a zero magnetic field, resulting in ultrahigh mobility (∼10^{7} cm^{2} V^{-1} s^{-1}). In an applied magnetic field, an anomalous Nernst effect is predicted to arise from the Berry curvature associated with the Weyl nodes. We report the observation of a large anomalous Nernst effect in Cd_{3}As_{2}. Both the anomalous Nernst signal and transport relaxation time τ_{tr} begin to increase rapidly at ∼50 K. This suggests a close relation between the protection mechanism and the anomalous Nernst effect. In a field, the quantum oscillations of bulk states display a beating effect, suggesting that the Dirac nodes split into Weyl states, allowing the Berry curvature to be observed as an anomalous Nernst effect.
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Affiliation(s)
- Tian Liang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Jingjing Lin
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Quinn Gibson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Tong Gao
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Max Hirschberger
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Minhao Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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21
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Sanders MB, Krizan JW, Plumb KW, McQueen TM, Cava RJ. NaSrMn 2F 7, NaCaFe 2F 7, and NaSrFe 2F 7: novel single crystal pyrochlore antiferromagnets. J Phys Condens Matter 2017; 29:045801. [PMID: 27875333 DOI: 10.1088/1361-648x/29/4/045801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The crystal structures and magnetic properties of three previously unreported A2B2F7 pyrochlore materials, NaSrMn2F7, NaCaFe2F7, and NaSrFe2F7 are presented. In these compounds, either S = 2Fe2+ or S = 5/2Mn2+ is on the B site, while nonmagnetic Na and Ca (Na and Sr) are disordered on the A site. The materials, which were grown as crystals via the floating zone method, display high effective magnetic moments and large Curie-Weiss thetas. Despite these characteristics, no ordering transition is detected. However, freezing of the magnetic spins, characterized by peaks in the susceptibility or specific heat, is observed at very low temperatures. The empirical frustration index, f = -θ CW/T f, for the materials are 36 (NaSrMn2F7), 27 (NaSrFe2F7), and 19 (NaCaFe2F7). AC susceptibility, DC susceptibility, and heat capacity measurements are used to characterize the observed spin glass behavior. The results suggest that the compounds are frustrated pyrochlore antiferromagnets with weak bond disorder. The magnetic phenomena that these fluoride pyrochlores exhibit, in addition to their availability as relatively large single crystals, make them promising candidates for the study of geometric magnetic frustration.
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Affiliation(s)
- M B Sanders
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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22
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Xie W, Winiarski MJ, Klimczuk T, Cava RJ. A tetragonal polymorph of SrMn2P2made under high pressure – theory and experiment in harmony. Dalton Trans 2017; 46:6835-6838. [DOI: 10.1039/c7dt00781g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A trigonal–tetragonal phase transition in SrMn2P2is proposed and confirmed experimentally under high pressure. At ambient pressure, SrMn2P2crystallizes in the primitive trigonal La2O3structure type (space groupP3̄m1) in blue. Under high pressure, the tetragonal ThCr2Si2structure type (space groupI4/mmm) in red is more stable.
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Affiliation(s)
- Weiwei Xie
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
| | - Michał J. Winiarski
- Faculty of Applied Physics and Mathematics
- Gdansk University of Technology
- 80-233 Gdansk
- Poland
| | - Tomasz Klimczuk
- Faculty of Applied Physics and Mathematics
- Gdansk University of Technology
- 80-233 Gdansk
- Poland
| | - R. J. Cava
- Department of Chemistry
- Princeton University
- Princeton
- USA
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23
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Abstract
Previously unreported σ-phases in the ternary niobium-based systems Nb–X–Ga for X = Ru, Rh, Pd, Ir, Pt, Au, and Nb–X–Al for X = Ir, and Pt are presented, prepared by arc-melting followed by annealing at 1000 °C for 1 week.
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Affiliation(s)
| | - Weiwei Xie
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
| | - Tomasz Klimczuk
- Department of Physics
- Gdansk University of Technology
- Gdansk
- Poland 80-233
| | - R. J. Cava
- Department of Chemistry
- Princeton University
- Princeton
- USA
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24
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Hirschberger M, Kushwaha S, Wang Z, Gibson Q, Liang S, Belvin CA, Bernevig BA, Cava RJ, Ong NP. The chiral anomaly and thermopower of Weyl fermions in the half-Heusler GdPtBi. Nat Mater 2016; 15:1161-1165. [PMID: 27348578 DOI: 10.1038/nmat4684] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 05/27/2016] [Indexed: 06/06/2023]
Abstract
The Dirac and Weyl semimetals are unusual materials in which the nodes of the bulk states are protected against gap formation by crystalline symmetry. The chiral anomaly, predicted to occur in both systems, was recently observed as a negative longitudinal magnetoresistance (LMR) in Na3Bi (ref. ) and in TaAs (ref. ). An important issue is whether Weyl physics appears in a broader class of materials. We report evidence for the chiral anomaly in the half-Heusler GdPtBi. In zero field, GdPtBi is a zero-gap semiconductor with quadratic bands. In a magnetic field, the Zeeman energy leads to Weyl nodes. We have observed a large negative LMR with the field-steering properties specific to the chiral anomaly. The chiral anomaly also induces strong suppression of the thermopower. We report a detailed study of the thermoelectric response function αxx of Weyl fermions. The scheme of creating Weyl nodes from quadratic bands suggests that the chiral anomaly may be observable in a broad class of semimetals.
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Affiliation(s)
- Max Hirschberger
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Satya Kushwaha
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Zhijun Wang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Quinn Gibson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Sihang Liang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Carina A Belvin
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - B A Bernevig
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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25
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Feldman BE, Randeria MT, Gyenis A, Wu F, Ji H, Cava RJ, MacDonald AH, Yazdani A. Observation of a nematic quantum Hall liquid on the surface of bismuth. Science 2016; 354:316-321. [DOI: 10.1126/science.aag1715] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/23/2016] [Indexed: 11/02/2022]
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26
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Akrap A, Hakl M, Tchoumakov S, Crassee I, Kuba J, Goerbig MO, Homes CC, Caha O, Novák J, Teppe F, Desrat W, Koohpayeh S, Wu L, Armitage NP, Nateprov A, Arushanov E, Gibson QD, Cava RJ, van der Marel D, Piot BA, Faugeras C, Martinez G, Potemski M, Orlita M. Magneto-Optical Signature of Massless Kane Electrons in Cd_{3}As_{2}. Phys Rev Lett 2016; 117:136401. [PMID: 27715109 DOI: 10.1103/physrevlett.117.136401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Indexed: 06/06/2023]
Abstract
We report on optical reflectivity experiments performed on Cd_{3}As_{2} over a broad range of photon energies and magnetic fields. The observed response clearly indicates the presence of 3D massless charge carriers. The specific cyclotron resonance absorption in the quantum limit implies that we are probing massless Kane electrons rather than symmetry-protected 3D Dirac particles. The latter may appear at a smaller energy scale and are not directly observed in our infrared experiments.
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Affiliation(s)
- A Akrap
- DQMP, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - M Hakl
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - S Tchoumakov
- LPS, Université Paris-Sud, Université Paris-Saclay, CNRS UMR 8502, 91405 Orsay, France
| | - I Crassee
- GAP-Biophotonics, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - J Kuba
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
- CEITEC BUT, Brno University of Technology, 616 00 Brno, Czech Republic
| | - M O Goerbig
- LPS, Université Paris-Sud, Université Paris-Saclay, CNRS UMR 8502, 91405 Orsay, France
| | - C C Homes
- CMPMS, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - O Caha
- CEITEC MU, Masaryk University, Faculty of Science, 61137 Brno, Czech Republic
| | - J Novák
- CEITEC MU, Masaryk University, Faculty of Science, 61137 Brno, Czech Republic
| | - F Teppe
- Laboratoire Charles Coulomb, CNRS, Université Montpellier, 34095 Montpellier, France
| | - W Desrat
- Laboratoire Charles Coulomb, CNRS, Université Montpellier, 34095 Montpellier, France
| | - S Koohpayeh
- The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - L Wu
- The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - N P Armitage
- The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - A Nateprov
- Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028 Chisinau, Moldova
| | - E Arushanov
- Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028 Chisinau, Moldova
| | - Q D Gibson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | | | - B A Piot
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - C Faugeras
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - G Martinez
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Orlita
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
- Institute of Physics, Charles University in Prague, 12116 Prague, Czech Republic
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27
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Bradlyn B, Cano J, Wang Z, Vergniory MG, Felser C, Cava RJ, Bernevig BA. Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals. Science 2016; 353:aaf5037. [DOI: 10.1126/science.aaf5037] [Citation(s) in RCA: 703] [Impact Index Per Article: 87.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 07/05/2016] [Indexed: 11/02/2022]
Affiliation(s)
- Barry Bradlyn
- Princeton Center for Theoretical Science, Princeton University, Princeton, NJ 08544, USA
| | - Jennifer Cano
- Princeton Center for Theoretical Science, Princeton University, Princeton, NJ 08544, USA
| | - Zhijun Wang
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - M. G. Vergniory
- Donostia International Physics Center, P. Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
| | - C. Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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28
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Xu SY, Liu C, Alidoust N, Neupane M, Qian D, Belopolski I, Denlinger JD, Wang YJ, Lin H, Wray LA, Landolt G, Slomski B, Dil JH, Marcinkova A, Morosan E, Gibson Q, Sankar R, Chou FC, Cava RJ, Bansil A, Hasan MZ. Corrigendum: Observation of a topological crystalline insulator phase and topological phase transition in Pb1-xSnxTe. Nat Commun 2016; 7:12505. [PMID: 27489130 PMCID: PMC5155670 DOI: 10.1038/ncomms12505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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29
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Winiarski MJ, Wiendlocha B, Gołąb S, Kushwaha SK, Wiśniewski P, Kaczorowski D, Thompson JD, Cava RJ, Klimczuk T. Superconductivity in CaBi2. Phys Chem Chem Phys 2016; 18:21737-45. [PMID: 27435423 DOI: 10.1039/c6cp02856j] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Superconductivity is observed with critical temperature Tc = 2.0 K in self-flux-grown single crystals of CaBi2. This material adopts the ZrSi2 structure type with lattice parameters a = 4.696(1) Å, b = 17.081(2) Å and c = 4.611(1) Å. The crystals of CaBi2 were studied by means of magnetic susceptibility, specific heat and electrical resistivity measurements. The heat capacity jump at Tc is ΔC/γTc = 1.41, confirming bulk superconductivity; the Sommerfeld coefficient γ = 4.1 mJ mol(-1) K(-2) and the Debye temperature ΘD = 157 K. The electron-phonon coupling strength is λel-ph = 0.59, and the thermodynamic critical field Hc is low, between 111 and 124 Oe CaBi2 is a moderate coupling type-I superconductor. Results of electronic structure calculations are reported and charge densities, electronic bands, densities of states and Fermi surfaces are discussed, focusing on the effects of spin-orbit coupling and electronic property anisotropy. We find a mixed quasi-2D + 3D character in the electronic structure, which reflects the layered crystal structure of the material.
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Affiliation(s)
- M J Winiarski
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.
| | - B Wiendlocha
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059 Krakow, Poland
| | - S Gołąb
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059 Krakow, Poland
| | - S K Kushwaha
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - P Wiśniewski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PNr 1410, 50-950 Wrocław, Poland
| | - D Kaczorowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PNr 1410, 50-950 Wrocław, Poland
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - T Klimczuk
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.
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30
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Abstract
We report the structure and magnetic properties of two new iridium-based honeycomb Delafossite compounds, Cu3NaIr2O6 and Cu3LiIr2O6, formed by a topotactic cation exchange reaction. The starting materials Na2IrO3 and Li2IrO3, which are based on layers of IrO6 octahedra in a honeycomb lattice separated by layers of alkali ions, are transformed to the title compounds by a topotactic exchange reaction through heating with CuCl below 450 °C; higher temperature reactions cause decomposition. The new compounds display dramatically different magnetic behavior from their parent compounds - Cu3NaIr2O6 has a ferromagnetic like magnetic transition at 10 K, while Cu3LiIr2O6 retains the antiferromagnetic transition temperature of its parent compound but displays significantly stronger dominance of antiferromagnetic coupling between spins. These results reveal that a surprising difference in the magnetic interactions between the magnetic Ir ions has been induced by a change in the non-magnetic interlayer species. A combination of neutron and X-ray powder diffraction is used for the structure refinement of Cu3NaIr2O6 and both compounds are compared to their parent materials.
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Affiliation(s)
- John H Roudebush
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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31
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Kushwaha SK, Pletikosić I, Liang T, Gyenis A, Lapidus SH, Tian Y, Zhao H, Burch KS, Lin J, Wang W, Ji H, Fedorov AV, Yazdani A, Ong NP, Valla T, Cava RJ. Sn-doped Bi1.1Sb0.9Te2S bulk crystal topological insulator with excellent properties. Nat Commun 2016; 7:11456. [PMID: 27118032 PMCID: PMC4853473 DOI: 10.1038/ncomms11456] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 03/30/2016] [Indexed: 12/03/2022] Open
Abstract
A long-standing issue in topological insulator research has been to find a bulk single crystal material that provides a high-quality platform for characterizing topological surface states without interference from bulk electronic states. This material would ideally be a bulk insulator, have a surface state Dirac point energy well isolated from the bulk valence and conduction bands, display quantum oscillations from the surface state electrons and be growable as large, high-quality bulk single crystals. Here we show that this material obstacle is overcome by bulk crystals of lightly Sn-doped Bi1.1Sb0.9Te2S grown by the vertical Bridgman method. We characterize Sn-BSTS via angle-resolved photoemission spectroscopy, scanning tunnelling microscopy, transport studies, X-ray diffraction and Raman scattering. We present this material as a high-quality topological insulator that can be reliably grown as bulk single crystals and thus studied by many researchers interested in topological surface states. An ideal topological insulator possesses an insulating bulk and a unique conducting surface however such behaviour is typically inhibited by bulk conduction due to defects. Here, the authors show that Sn-doped Bi1.1Sb0.9Te2S grown by the vertical Bridgman technique might overcome this hurdle.
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Affiliation(s)
- S K Kushwaha
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - I Pletikosić
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.,Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Department, Upton, New York 11973, USA
| | - T Liang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - A Gyenis
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - S H Lapidus
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yao Tian
- Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7
| | - He Zhao
- Department of Physics, Boston College, Boston, Massachusetts 02467-3804, USA
| | - K S Burch
- Department of Physics, Boston College, Boston, Massachusetts 02467-3804, USA
| | - Jingjing Lin
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Wudi Wang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Huiwen Ji
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - A V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ali Yazdani
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - T Valla
- Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Department, Upton, New York 11973, USA
| | - R J Cava
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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32
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Abstract
Spatial symmetries in crystals may be distinguished by whether they preserve the spatial origin. Here we study spatial symmetries that translate the origin by a fraction of the lattice period, and find that these non-symmorphic symmetries protect an exotic surface fermion whose dispersion relation is shaped like an hourglass; surface bands connect one hourglass to the next in an unbreakable zigzag pattern. These 'hourglass' fermions are formed in the large-gap insulators, KHgX (X = As, Sb, Bi), which we propose as the first material class whose band topology relies on non-symmorphic symmetries. Besides the hourglass fermion, another surface of KHgX manifests a three-dimensional generalization of the quantum spin Hall effect, which has previously been observed only in two-dimensional crystals. To describe the bulk topology of non-symmorphic crystals, we propose a non-Abelian generalization of the geometric theory of polarization. Our non-trivial topology originates from an inversion of the rotational quantum numbers, which we propose as a criterion in the search for topological materials.
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Affiliation(s)
- Zhijun Wang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - A Alexandradinata
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.,Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, USA
| | - B Andrei Bernevig
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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33
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Gordon RT, Vannette MD, Strychalska J, Klimczuk T, Cava RJ, Prozorov R. Superconductivity and itinerant ferromagnetism of Y9Co7 probed by ac susceptibility. J Phys Condens Matter 2016; 28:166006. [PMID: 27022686 DOI: 10.1088/0953-8984/28/16/166006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The ac magnetic susceptibility of a single crystal sample of the compound Y9Co7 has been measured in applied dc fields ranging from 0-6.7 kOe by utilizing a tunnel diode resonator circuit. In agreement with previous measurements on this material, a superconducting transition has been observed to occur at T(SC)≈2.5 K. A broad maximum has been observed in the zero field susceptibility measurements from 2.5 K < T < 8 K and its behavior with applied dc magnetic fields is consistent with that of the itinerant ferromagnet ZrZn2, which supports previous claims of itinerant ferromagnetism in this compound. The susceptibility has also been measured as a function of applied magnetic field and the results indicate that the actual Curie temperature for this system is higher than that suggested by previous reports based on Arrott plots constructed from dc magnetization.
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Affiliation(s)
- R T Gordon
- Department of Physics, Western Illinois University, Macomb, IL 61455, USA
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34
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Qi Y, Naumov PG, Ali MN, Rajamathi CR, Schnelle W, Barkalov O, Hanfland M, Wu SC, Shekhar C, Sun Y, Süß V, Schmidt M, Schwarz U, Pippel E, Werner P, Hillebrand R, Förster T, Kampert E, Parkin S, Cava RJ, Felser C, Yan B, Medvedev SA. Superconductivity in Weyl semimetal candidate MoTe2. Nat Commun 2016; 7:11038. [PMID: 26972450 PMCID: PMC4793082 DOI: 10.1038/ncomms11038] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 02/15/2016] [Indexed: 12/25/2022] Open
Abstract
Transition metal dichalcogenides have attracted research interest over the last few decades due to their interesting structural chemistry, unusual electronic properties, rich intercalation chemistry and wide spectrum of potential applications. Despite the fact that the majority of related research focuses on semiconducting transition-metal dichalcogenides (for example, MoS2), recently discovered unexpected properties of WTe2 are provoking strong interest in semimetallic transition metal dichalcogenides featuring large magnetoresistance, pressure-driven superconductivity and Weyl semimetal states. We investigate the sister compound of WTe2, MoTe2, predicted to be a Weyl semimetal and a quantum spin Hall insulator in bulk and monolayer form, respectively. We find that bulk MoTe2 exhibits superconductivity with a transition temperature of 0.10 K. Application of external pressure dramatically enhances the transition temperature up to maximum value of 8.2 K at 11.7 GPa. The observed dome-shaped superconductivity phase diagram provides insights into the interplay between superconductivity and topological physics.
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Affiliation(s)
- Yanpeng Qi
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Pavel G. Naumov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Mazhar N. Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Catherine R. Rajamathi
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Walter Schnelle
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Oleg Barkalov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Michael Hanfland
- European Synchrotron Radiation Facility, BP 220, 38043 Grenoble, France
| | - Shu-Chun Wu
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Chandra Shekhar
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Yan Sun
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Vicky Süß
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Marcus Schmidt
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Ulrich Schwarz
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Eckhard Pippel
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | - Peter Werner
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | | | - Tobias Förster
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Erik Kampert
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Stuart Parkin
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Binghai Yan
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
| | - Sergey A. Medvedev
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
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35
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Rowley SE, Hadjimichael M, Ali MN, Durmaz YC, Lashley JC, Cava RJ, Scott JF. Quantum criticality in a uniaxial organic ferroelectric. J Phys Condens Matter 2015; 27:395901. [PMID: 26360383 DOI: 10.1088/0953-8984/27/39/395901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Tris-sarcosine calcium chloride (TSCC) is a highly uniaxial ferroelectric with a Curie temperature of approximately 130 K. By suppressing ferroelectricity with bromine substitution on the chlorine sites, pure single crystals were tuned through a ferroelectric quantum phase transition. The resulting quantum critical regime was investigated in detail and was found to persist up to temperatures of at least 30-40 K. The nature of long-range dipole interactions in uniaxial materials, which lead to non-analytical terms in the free-energy expansion in the polarization, predict a dielectric susceptibility varying as 1/T(3)close to the quantum critical point. Rather than this, we find that the dielectric susceptibility varies as 1/T(2) as expected and observed in better known multi-axial systems. We explain this result by identifying the ultra-weak nature of the dipole moments in the TSCC family of crystals. Interestingly, we observe a shallow minimum in the inverse dielectric function at low temperatures close to the quantum critical point in paraelectric samples that may be attributed to the coupling of quantum polarization and strain fields. Finally, we present results of the heat capacity and electro-caloric effect and explain how the time dependence of the polarization in ferroelectrics and paraelectrics should be considered when making quantitative estimates of temperature changes induced by applied electric fields.
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Affiliation(s)
- S E Rowley
- Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK. CBPF, Rua Dr Xavier Sigaud 150, Urca, Rio de Janeiro, 22290-180, Brazil
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36
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Abstract
The 3-layer rhombohedral (3R) polytype of TaSe2-x Te x is known to display a superconducting transition temperature that is between 6 and 17 times higher than that of the two-layer hexagonal (2H) polytype. The remarkable difference in T c, although clearly associated with a difference in polytype, could have been due to an electronic effect specific to the Te-Se substitution. Here we report that small amounts of Mo or W doping lead to a 2H to 3R polytype transition in Ta1-x Mo x Se2 and Ta1-x W x Se2. The 3R polytype materials are again found to have substantially higher T c (~2 K for Ta0.9W0.1Se2 and Ta0.9Mo0.1Se2) than the 2H material (0.15 K), eliminating the possibility that any special characteristics of the Te/Se substitution are responsible for the dramatic difference in T c. We infer that a three-layer stacking sequence is strongly preferred for superconductivity over a two-layer stacking sequence in the TaSe2 system.
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Affiliation(s)
- Huixia Luo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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37
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Xiong J, Kushwaha SK, Liang T, Krizan JW, Hirschberger M, Wang W, Cava RJ, Ong NP. Evidence for the chiral anomaly in the Dirac semimetal Na₃Bi. Science 2015; 350:413-6. [PMID: 26338798 DOI: 10.1126/science.aac6089] [Citation(s) in RCA: 252] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 08/19/2015] [Indexed: 11/02/2022]
Abstract
In a Dirac semimetal, each Dirac node is resolved into two Weyl nodes with opposite "handedness" or chirality. The two chiral populations do not mix. However, in parallel electric and magnetic fields ( E: || B: ), charge is predicted to flow between the Weyl nodes, leading to negative magnetoresistance. This "axial" current is the chiral (Adler-Bell-Jackiw) anomaly investigated in quantum field theory. We report the observation of a large, negative longitudinal magnetoresistance in the Dirac semimetal Na3Bi. The negative magnetoresistance is acutely sensitive to deviations of the direction of B: from E: and is incompatible with conventional transport. By rotating E: (as well as B: ), we show that it is consistent with the prediction of the chiral anomaly.
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Affiliation(s)
- Jun Xiong
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Satya K Kushwaha
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Tian Liang
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Jason W Krizan
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Max Hirschberger
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Wudi Wang
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, NJ 08544, USA.
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38
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Abstract
We report the crystal growth, by the Bridgeman-Stockbarger method, and the basic magnetic properties of a new cobalt-based pyrochlore, NaSrCo2F7. Single-crystal structure determination shows that Na and Sr are completely disordered on the non-magnetic large atom A sites, while magnetic [Formula: see text] Co(2+) fully occupies the pyrochlore lattice B sites. NaSrCo2F7 displays strong antiferromagnetic interactions ([Formula: see text]), a large effective moment ([Formula: see text]), and no spin freezing until 3 K. Thus, NaSrCo2F7 is a geometrically frustrated antiferromagnet with a frustration index [Formula: see text]. Ac susceptibility, dc susceptibility, and heat capacity are utilized to characterize the spin freezing. We argue that NaSrCo2F7 and the related material NaCaCo2F7 are examples of frustrated pyrochlore antiferromagnets with weak bond disorder.
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Affiliation(s)
- J W Krizan
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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39
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Haldolaarachchige N, Gibson Q, Schoop LM, Luo H, Cava RJ. Characterization of the heavy metal pyrochlore lattice superconductor CaIr2. J Phys Condens Matter 2015; 27:185701. [PMID: 25880601 DOI: 10.1088/0953-8984/27/18/185701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the electronic properties of the cubic laves phase superconductor CaIr2(Tc = 5.8 K), in which the Ir atoms have a pyrochlore lattice. The estimated superconducting parameters obtained from magnetization and specific heat measurements indicate that CaIr2 is a weakly coupled BCS superconductor. Electronic band structure calculations show that the Ir d-states are dominant at the Fermi level, creating a complex Fermi surface that is impacted substantially by spin-orbit coupling.
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40
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Affiliation(s)
- Max Hirschberger
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Jason W. Krizan
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - N. P. Ong
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
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41
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Roudebush JH, Sahasrabudhe G, Bergman SL, Cava RJ. Rhombohedral Polytypes of the Layered Honeycomb Delafossites with Optical Brilliance in the Visible. Inorg Chem 2015; 54:3203-10. [DOI: 10.1021/ic502790n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- John H. Roudebush
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Girija Sahasrabudhe
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Susanna L. Bergman
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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42
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Liang T, Gibson Q, Ali MN, Liu M, Cava RJ, Ong NP. Ultrahigh mobility and giant magnetoresistance in the Dirac semimetal Cd3As2. Nat Mater 2015; 14:280-284. [PMID: 25419815 DOI: 10.1038/nmat4143] [Citation(s) in RCA: 317] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 10/20/2014] [Indexed: 05/28/2023]
Abstract
Dirac and Weyl semimetals are 3D analogues of graphene in which crystalline symmetry protects the nodes against gap formation. Na3Bi and Cd3As2 were predicted to be Dirac semimetals, and recently confirmed to be so by photoemission experiments. Several novel transport properties in a magnetic field have been proposed for Dirac semimetals. Here, we report a property of Cd3As2 that was unpredicted, namely a remarkable protection mechanism that strongly suppresses backscattering in zero magnetic field. In single crystals, the protection results in ultrahigh mobility, 9 × 10(6) cm(2) V(-1) s(-1) at 5 K. Suppression of backscattering results in a transport lifetime 10(4) times longer than the quantum lifetime. The lifting of this protection by the applied magnetic field leads to a very large magnetoresistance. We discuss how this may relate to changes to the Fermi surface induced by the applied magnetic field.
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Affiliation(s)
- Tian Liang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Quinn Gibson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Mazhar N Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Minhao Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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43
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Arguello CJ, Rosenthal EP, Andrade EF, Jin W, Yeh PC, Zaki N, Jia S, Cava RJ, Fernandes RM, Millis AJ, Valla T, Osgood RM, Pasupathy AN. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe2. Phys Rev Lett 2015; 114:037001. [PMID: 25659014 DOI: 10.1103/physrevlett.114.037001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 06/04/2023]
Abstract
We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe2 that we measure by scanning tunneling spectroscopic imaging. We show, from the momentum and energy dependence of the quasiparticle interference, that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe2. We demonstrate that, by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wave vector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe2, we use this combination to confirm that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the charge density wave ordering wave vector.
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Affiliation(s)
- C J Arguello
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - E P Rosenthal
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - E F Andrade
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - W Jin
- Department of Applied Physics and Applied Math, Columbia University, New York, New York 10027, USA
| | - P C Yeh
- Department of Applied Physics and Applied Math, Columbia University, New York, New York 10027, USA
| | - N Zaki
- Department of Electrical Engineering, Columbia University, New York, New York 10027, USA
| | - S Jia
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - A J Millis
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - T Valla
- Brookhaven National Laboratory, Upton, New York 11973, USA
| | - R M Osgood
- Department of Electrical Engineering, Columbia University, New York, New York 10027, USA and Department of Chemistry, Princeton University, Princeton, New Jersey 08540, USA
| | - A N Pasupathy
- Department of Physics, Columbia University, New York, New York 10027, USA
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Pletikosić I, Ali MN, Fedorov AV, Cava RJ, Valla T. Electronic structure basis for the extraordinary magnetoresistance in WTe2. Phys Rev Lett 2014; 113:216601. [PMID: 25479512 DOI: 10.1103/physrevlett.113.216601] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Indexed: 05/13/2023]
Abstract
The electronic structure basis of the extremely large magnetoresistance in layered nonmagnetic tungsten ditelluride has been investigated by angle-resolved photoelectron spectroscopy. Hole and electron pockets of approximately the same size were found at low temperatures, suggesting that carrier compensation should be considered the primary source of the effect. The material exhibits a highly anisotropic Fermi surface from which the pronounced anisotropy of the magnetoresistance follows. A change in the Fermi surface with temperature was found and a high-density-of-states band that may take over conduction at higher temperatures and cause the observed turn-on behavior of the magnetoresistance in WTe2 was identified.
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Affiliation(s)
- I Pletikosić
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Mazhar N Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - A V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - T Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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45
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Klimczuk T, Walter O, Müchler L, Krizan JW, Kinnart F, Cava RJ. Crystal structure and electronic structure of CePt2In7. J Phys Condens Matter 2014; 26:402201. [PMID: 25211386 DOI: 10.1088/0953-8984/26/40/402201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report a corrected crystal structure for the CePt(2)In(7) superconductor, refined from single crystal x-ray diffraction data. The corrected crystal structure shows a different Pt-In stacking along the c-direction in this layered material than was previously reported. In addition, all of the atomic sites are fully occupied with no evidence of atom site mixing, resolving a discrepancy between the observed high resistivity ratio of the material and the atomic disorder present in the previous structural model. The Ce-Pt distance and coordination is typical of that seen in all other reported Ce(n)M(m)In(3n+2 m) compounds. Our band structure calculations based on the correct structure reveal three bands at the Fermi level that are more 3D than those previously proposed, and density functional theory (DFT) calculations show that the new structure has a significantly lower energy.
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Affiliation(s)
- T Klimczuk
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland
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46
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Seibel EM, Roudebush JH, Ali MN, Ross KA, Cava RJ. Structure and Magnetic Properties of the Spin-1/2-Based Honeycomb NaNi2BiO6-δ and Its Hydrate NaNi2BiO6-δ·1.7H2O. Inorg Chem 2014; 53:10989-95. [DOI: 10.1021/ic501390r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elizabeth M. Seibel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - John H. Roudebush
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mazhar N. Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - K. A. Ross
- Institute for Quantum Matter and Department
of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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47
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Ali MN, Xiong J, Flynn S, Tao J, Gibson QD, Schoop LM, Liang T, Haldolaarachchige N, Hirschberger M, Ong NP, Cava RJ. Large, non-saturating magnetoresistance in WTe2. Nature 2014; 514:205-8. [DOI: 10.1038/nature13763] [Citation(s) in RCA: 1137] [Impact Index Per Article: 113.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/28/2014] [Indexed: 11/09/2022]
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48
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Gibson QD, Evtushinsky D, Yaresko AN, Zabolotnyy VB, Ali MN, Fuccillo MK, Van den Brink J, Büchner B, Cava RJ, Borisenko SV. Quasi one dimensional Dirac electrons on the surface of Ru₂Sn₃. Sci Rep 2014; 4:5168. [PMID: 24893841 PMCID: PMC4044652 DOI: 10.1038/srep05168] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 05/14/2014] [Indexed: 11/09/2022] Open
Abstract
We present an ARPES study of the surface states of Ru2Sn3, a new type of a strong 3D topological insulator (TI). In contrast to currently known 3D TIs, which display two-dimensional Dirac cones with linear isotropic dispersions crossing through one point in the surface Brillouin Zone (SBZ), the surface states on Ru2Sn3 are highly anisotropic, displaying an almost flat dispersion along certain high-symmetry directions. This results in quasi-one dimensional (1D) Dirac electronic states throughout the SBZ that we argue are inherited from features in the bulk electronic structure of Ru2Sn3 where the bulk conduction bands are highly anisotropic. Unlike previous experimentally characterized TIs, the topological surface states of Ru2Sn3 are the result of a d-p band inversion rather than an s-p band inversion. The observed surface states are the topological equivalent to a single 2D Dirac cone at the surface Brillouin zone.
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Affiliation(s)
- Q. D. Gibson
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
| | - D. Evtushinsky
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - A. N. Yaresko
- Max-Planck-Institut für Festkörperforschung Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - V. B. Zabolotnyy
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - Mazhar N. Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
| | - M. K. Fuccillo
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
| | - J. Van den Brink
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - B. Büchner
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
- Institute for Solid State Physics, Technical University Dresden, D-01171 Dresden, Germany
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
| | - S. V. Borisenko
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
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Kushwaha SK, Krizan JW, Xiong J, Klimczuk T, Gibson QD, Liang T, Ong NP, Cava RJ. Superconducting properties and electronic structure of NaBi. J Phys Condens Matter 2014; 26:212201. [PMID: 24804822 DOI: 10.1088/0953-8984/26/21/212201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Resistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. T(c), the electronic contribution to the specific heat γ, the ΔC(p)/γT(c) ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol(-1) K(-2), 0.78, and 140 K respectively. The calculated electron-phonon coupling constant (λ(ep) = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence length are found to be 250 Oe and 115 nm, respectively. Electronic structure calculations show NaBi to be a good metal, in agreement with the experiments; the p(x) and p(y) orbitals of Bi dominate the electronic states at the Fermi Energy.
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Affiliation(s)
- S K Kushwaha
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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50
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Luo H, Gibson Q, Krizan J, Cava RJ. Ferromagnetism in Mn-doped Sb(2)Te. J Phys Condens Matter 2014; 26:206002. [PMID: 24786568 DOI: 10.1088/0953-8984/26/20/206002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report that Sb2Te, a natural superlattice phase consisting of two elemental Sb2 layers interleaved with single Sb2Te3 layers, becomes ferromagnetic at low temperatures on doping with small percentages of Mn. Ferromagnetism appears for Mn concentrations as low as Sb1.98Mn0.02Te, where a ferromagnetic Tc of ~8.6 K is observed. Tc decreases with increasing Mn content in the stoichiometric materials but increases with increasing Te excess in materials of the type Sb1.93-yMn0.07Te1+y, starting at ~3 K at y = 0 and reaching a Tc of ~8.9 K at y = 0.06.
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Affiliation(s)
- H Luo
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
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