Abstract
The discovery of graphene has stimulated enormous interest in two-dimensional (2D) electron gas with linear band dispersion. However, to date, 2D Dirac semimetals are still very rare due to the fact that 2D Dirac states are generally fragile against perturbations such as spin-orbit coupling. Nonsymmorphic crystal symmetries can enforce the formation of Dirac nodes, providing another route to establishing symmetry-protected Dirac states in 2D materials. Here, we report the symmetry-protected Dirac states in nonsymmorphic α-antimonene (Sb monolayer). The antimonene was synthesized by the method of molecular beam epitaxy. 2D Dirac states with large anisotropy were observed by angle-resolved photoemission spectroscopy. The Dirac states in α-antimonene are spin-orbit coupled in contrast to the spinless Dirac states in graphene. The result extends the graphene physics into a family of 2D materials where spin-orbit coupling is present.
| Original language | English |
|---|---|
| Article number | A66 |
| Journal | Physical Review B |
| Volume | 104 |
| Issue number | 20 |
| DOIs | |
| State | Published - Nov 15 2021 |
| Externally published | Yes |
Funding
G.B. was supported by the U.S. National Science Foundation under Grant No. NSF-DMR-1809160. T.-R.C. was supported by the Young Scholar Fellowship Program from the Ministry of Science and Technology (MOST) in Taiwan, under a MOST grant for the Columbus Program, No. MOST110-2636-M-006-016, NCKU, Taiwan, and National Center for Theoretical Sciences, Taiwan. Work at NCKU was supported by the MOST, Taiwan, under Grant No. MOST107-2627-E-006-001, and Higher Education Sprout Project, Ministry of Education to the Headquarters of University Advancement at NCKU. S.A.Y. was supported by Singapore MOE AcRF Tier 2 (MOE2019-T2-1-001).