Publication Date
4-15-2020
Department
Ames Laboratory; Physics and Astronomy
Campus Units
Ames Laboratory, Physics and Astronomy
OSTI ID+
1616740
Report Number
IS-J 9990
DOI
10.1103/PhysRevB.101.161109
Journal Title
Physical Review B
Volume Number
101
Issue Number
16
First Page
161109(R)
Abstract
We used angle-resolved photoemission spectroscopy (ARPES) and density functional theory calculations to study the electronic properties of MnBi2Te4, a material that was predicted to be an intrinsic antiferromagnetic (AFM) topological insulator. In striking contrast to earlier literature showing a full gap opening between two surface band manifolds on the (0001) surface, we observed a gapless Dirac surface state with a Dirac point sitting at EB=−280meV. Furthermore, our ARPES data revealed the existence of a second Dirac cone sitting closer to the Fermi level. Surprisingly, these surface states remain intact across the AFM transition. The presence of gapless Dirac states in this material may be caused by different ordering at the surface from the bulk or weaker magnetic coupling between the bulk and surface. Whereas the surface Dirac cones seem to be remarkably insensitive to the AFM ordering most likely due to weak coupling to magnetism, we did observe a splitting of the bulk band accompanying the AFM transition. With a moderately high ordering temperature and interesting gapless Dirac surface states, MnBi2Te4 provides a unique platform for studying the interplay between magnetic ordering and topology.
DOE Contract Number(s)
AC02-07CH11358; DMR-1420451; AC05-00OR22725
Language
en
Department of Energy Subject Categories
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Publisher
Iowa State University Digital Repository, Ames IA (United States)
