Dirac State Switching in Transition Metal Diarsenides
POSTER
Abstract
Topological semimetals exhibiting Dirac and Weyl fermions, which support low-energy quasi-particles in condensed matter physics, have been attracting intense research interest because of the exotic properties they possess like high magnetoresistance and high carrier mobilities. The transition metal diarsenides such as MoAs2 and WAs2 have been reported to feature very large magnetoresistance suggesting the possibility of topological quantum state in these materials. Here, we present the systematic electronic structure measurements of TAs2 (T = Mo, W) by using angle-resolved photoemission spectroscopy (ARPES) complemented by first-principles calculations. We observe a single Dirac surface state in MoAs2, which switches to trivial state for different cleaving surface. Interestingly, no Dirac surface state is observed in WAs2, despite its high magnetoresistance, highlighting the role of spin-orbit coupling in the electronic structure. Our study thus provides a new perspective on how cleavage plane and spin-orbit coupling drive changes in the electronic structures in low-symmetry systems.
*This project is supported by the Air Force Office of Scientific Research under award number FA9550-17-1-0415 and the National Science Foundation (NSF) CAREER award DMR-1847962.
Presenters
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Sabin Regmi
- Univ of Central Florida
- Physics, University of Central Florida
- University of Central Florida