2016/05/31 by Jayita Nayak, Shu-Chun Wu, Nitesh Kumar +8 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1038/ncomms13942
18 pages including the supplementary information, 4+4 figures
arxiv created 2016/08/12 · arxiv updated 2017/02/01
The rare-earth monopnictide LaBi exhibits exotic magneto-transport properties including an extremely large and anisotropic magnetoresistance. Experimental evidence for topological surface states is still missing although band inversions have been postulated to induce a topological phase in LaBi. By employing angle-resolved photoemission spectroscopy (ARPES) in conjunction with ab~initio calculations, we have revealed the existence of surface states of LaBi through the observation of three Dirac cones: two coexist at the corners and one appears at the center of the Brillouin zone. The odd number of surface Dirac cones is a direct consequence of the odd number of band inversions in the bulk band structure, thereby proving that LaBi is a topological, compensated semi-metal, which is equivalent to a time-reversal invariant topological insulator. Our findings provide insight into the topological surface states of LaBi's semi-metallicity and related magneto-transport properties.