DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Emergence of Nontrivial Low‐Energy Dirac Fermions in Antiferromagnetic EuCd 2 As 2

Journal Article · · Advanced Materials
ORCiD logo [1];  [2];  [3];  [4];  [4];  [4];  [5];  [6];  [7];  [2];  [8];  [5];  [5];  [1];  [9];  [2];  [9];  [9];  [5];  [10]
  1. Paul Scherrer Institute Swiss Light Source CH‐5232 Villigen PSI Switzerland, Institute of Condensed Matter Physics École Polytechnique Fédérale de Lausanne CH‐10 15 Lausanne Switzerland
  2. Department of Physics Applied Physics, and Astronomy Rensselaer Polytechnic Institute Troy NY 12180 USA
  3. Department of Materials Science and Engineering Stanford University Stanford CA 94305 USA
  4. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China, School of Physics University of Chinese Academy of Sciences Beijing 100190 China
  5. Paul Scherrer Institute Swiss Light Source CH‐5232 Villigen PSI Switzerland
  6. Physikalisches Institut Karlsruhe Institute of Technology 76131 Karlsruhe Germany
  7. Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201204 China
  8. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China, School of Physics University of Chinese Academy of Sciences Beijing 100190 China, Institut quantique Université de Sherbrooke 2500 boulevard de l'Université Sherbrooke Québec J1K 2R1 Canada
  9. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China, Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China
  10. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China, School of Physics University of Chinese Academy of Sciences Beijing 100190 China, Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China, CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing 100190 China

Abstract Parity‐time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realization of magnetic topological DSMs remains a major issue in topological material research. Here, combining angle‐resolved photoemission spectroscopy with density functional theory calculations, it is ascertained that band inversion induces a topologically nontrivial ground state in EuCd 2 As 2 . As a result, ideal magnetic Dirac fermions with simplest double cone structure near the Fermi level emerge in the antiferromagnetic (AFM) phase. The magnetic order breaks time reversal symmetry, but preserves inversion symmetry. The double degeneracy of the Dirac bands is protected by a combination of inversion, time‐reversal, and an additional translation operation. Moreover, the calculations show that a deviation of the magnetic moments from the c ‐axis leads to the breaking of C3 rotation symmetry, and thus, a small bandgap opens at the Dirac point in the bulk. In this case, the system hosts a novel state containing three different types of topological insulator: axion insulator, AFM topological crystalline insulator (TCI), and higher order topological insulator. The results provide an enlarged platform for the quest of topological Dirac fermions in a magnetic system.

Sponsoring Organization:
USDOE
Grant/Contract Number:
DESC0002623
OSTI ID:
1601506
Journal Information:
Advanced Materials, Journal Name: Advanced Materials Vol. 32 Journal Issue: 14; ISSN 0935-9648
Publisher:
Wiley Blackwell (John Wiley & Sons)Copyright Statement
Country of Publication:
Germany
Language:
English
Citation Metrics:
Cited by: 41 works
Citation information provided by
Web of Science

References (39)

Massive Dirac Fermion on the Surface of a Magnetically Doped Topological Insulator journal August 2010
Generalized Gradient Approximation Made Simple journal October 1996
Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal A B C Crystals journal September 2018
Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set journal July 1996
Weyl–Kondo semimetal in heavy-fermion systems journal December 2017
Three-dimensional Dirac semimetal and quantum transport in Cd 3 As 2 journal September 2013
Higher-order topological insulators journal June 2018
Z2 Topological Order and the Quantum Spin Hall Effect journal September 2005
Ruderman-Kittel-Kasuya-Yosida interaction in Weyl semimetals journal December 2015
Kondo effect in three-dimensional Dirac and Weyl systems journal September 2015
Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set journal October 1996
Discovery of a Three-Dimensional Topological Dirac Semimetal, Na3Bi journal January 2014
A 121Sb and 151Eu Mössbauer Spectroscopic Investigation of EuCd2X2 (X = P, As, Sb) and YbCd2Sb2 journal May 2011
Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3 journal November 2010
Spin-orbit interaction effect in the electronic structure of Bi 2 Te 3 observed by angle-resolved photoemission spectroscopy journal February 2008
Discovery of a Weyl fermion semimetal and topological Fermi arcs journal July 2015
Dirac semimetal and topological phase transitions in A 3 Bi ( A = Na , K, Rb) journal May 2012
Topological Insulators in Three Dimensions journal March 2007
Dirac semimetal in type-IV magnetic space groups journal November 2018
Antiferromagnetic topological insulators journal June 2010
Topological Axion States in the Magnetic Insulator MnBi 2 Te 4 with the Quantized Magnetoelectric Effect journal May 2019
Higher-order topological insulators and superconductors protected by inversion symmetry journal May 2018
Higher-Order Topology of the Axion Insulator EuIn 2 As 2 journal June 2019
Crystal and magnetic structure of CaCo 1.86 As 2 studied by x-ray and neutron diffraction journal November 2013
Symmetry-based indicators of band topology in the 230 space groups journal June 2017
RKKY interaction of magnetic impurities in multi-Weyl semimetals journal October 2017
Dirac fermions in an antiferromagnetic semimetal journal August 2016
Coupling of magnetic order and charge transport in the candidate Dirac semimetal EuCd 2 As 2 journal June 2018
Observation of Weyl nodes in TaAs journal August 2015
Anisotropic transport and optical spectroscopy study on antiferromagnetic triangular lattice EuCd 2 As 2 : An interplay between magnetism and charge transport properties journal July 2016
Intrinsic magnetic topological insulators in van der Waals layered MnBi 2 Te 4 -family materials journal June 2019
RKKY interaction of magnetic impurities in Dirac and Weyl semimetals journal December 2015
A stable three-dimensional topological Dirac semimetal Cd3As2 journal May 2014
A compact sub-Kelvin ultrahigh vacuum scanning tunneling microscope with high energy resolution and high stability journal October 2011
Topological semimetal in honeycomb lattice LnSI journal September 2017
Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd 2 As 2 journal July 2019
Anisotropic Dirac Fermions in a Bi Square Net of SrMnBi 2 journal September 2011
Metamagnetic transition in EuFe 2 As 2 single crystals journal February 2009
A Weyl Fermion semimetal with surface Fermi arcs in the transition metal monopnictide TaAs class journal June 2015