Realization of a Type‐II Nodal‐Line Semimetal in Mg3Bi2
Abstract
Nodal‐line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type‐I and type‐II Weyl semimetals, there are two types of NLSs. The type‐I NLS phase has been proposed and realized in many compounds, whereas the exotic type‐II NLS phase that strongly violates Lorentz symmetry has remained elusive. First‐principles calculations show that Mg3Bi2 is a material candidate for the type‐II NLS. The band crossing is close to the Fermi level and exhibits the type‐II nature of the nodal line in this material. Spin–orbit coupling generates only a small energy gap (≈35 meV) at the nodal points and does not negate the band dispersion of Mg3Bi2 that yields the type‐II nodal line. Based on this prediction, Mg3Bi2 single crystals are synthesized and the presence of the type‐II nodal lines in the material is confirmed. The angle‐resolved photoemission spectroscopy measurements agree well with the first‐principles results below the Fermi level and thus strongly suggest Mg3Bi2 as an ideal material platform for studying the as‐yet unstudied properties of type‐II nodal‐line semimetals.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 28, 2018
- Source ID
- 10.1002/advs.201800897
Entities
People
- Angus Huang
- Boris Sinkovic
- Guang Bian
- Horny‐tay Jeng
- Ivo Pletikosić
- Jonathan D Denlinger
- Robert Cava
- Satya K. Kushwaha
- Tai Kong
- Tay-Rong Chang
- Tonica Valla
- Weiwei Xie
Organizations
- Academia Sinica
- Army Research Office
- Brookhaven National Laboratory
- Lawrence Berkeley National Laboratory
- Louisiana State University
- Ministry of Science and Technology
- National Center for theoretical Sciences
- National Cheng Kung University
- National Science Foundation
- National Tsing Hua University
- Princeton University
- University of Connecticut
- University of Missouri