Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2 As2

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2 As2

© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bibliographische Detailangaben
Veröffentlicht in:Advanced materials (Deerfield Beach, Fla.). - 1998. - 32(2020), 14 vom: 30. Apr., Seite e1907565
1. Verfasser: Ma, Junzhang (VerfasserIn)
Weitere Verfasser: Wang, Han, Nie, Simin, Yi, Changjiang, Xu, Yuanfeng, Li, Hang, Jandke, Jasmin, Wulfhekel, Wulf, Huang, Yaobo, West, Damien, Richard, Pierre, Chikina, Alla, Strocov, Vladimir N, Mesot, Joël, Weng, Hongming, Zhang, Shengbai, Shi, Youguo, Qian, Tian, Shi, Ming, Ding, Hong
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2020
Zugriff auf das übergeordnete Werk:Advanced materials (Deerfield Beach, Fla.)
Schlagworte:Journal Article axion insulator condensed matter physics higher order topological insulator magnetic Dirac semimetal
Beschreibung
Zusammenfassung:© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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 EuCd2 As2 . 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
Beschreibung:Date Revised 30.09.2020
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1521-4095
DOI:10.1002/adma.201907565