Electronic structure of semi-metallic PtSe2 investigated with spin- and angle-resolved photoemission

The observation of extremely high and non-saturating magnetoresistance has sparked a renewed interest in compensated electron and hole pocket semimetals [1]. Here, we will present direct electronic structure measurements of 1T-structured PtSe2, a transition-metal dichalcogenide (TMD) compound. This was previously predicted to be semi-metallic with co-existing electron and hole pockets making up its the Fermi surface [2], but the details of its band structure have remained elusive to date. Unlike more intensely studied TMDs such as NbSe2\sout{ }/MoS2, its low-energy electronic structure is predicted to be dominated by chalcogen p-orbital, rather than transition-metal d-orbital, derived states. Nonetheless, we will show how spin-orbit coupling in the chalcogen shell still plays a major role in shaping its underlying electronic structure. Combining spin- with angle-resolved photoemission spectroscopy, we uncover its bulk electronic structure as well as revealing the formation of a number of topologically-protected states in this system. [1] M. N. Ali, et al. Nature 514, 205208 (2014). [2] D. Dai, et al. J. Solid State Chem. 173, 114 (2003).