Metal-chalcogen bond-length induced electronic phase transition from semiconductor to topological semimetal in ZrX2 (X=Se and Te)

Abstract

Topological transition-metal dichalcogenides have been the center of research interests in materials science, recent days, due to their potential applications in spintronics, optoelectronics, and quantum computations. In this paper, using angle resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations, we systematically studied the low-energy electronic structure of bulk ZrTe 2 . ARPES studies on ZrTe 2 demonstrate free charge carriers at the Fermi level, which is further confirmed by the DFT calculations. An equal hole and electron carrier density estimated from the ARPES data points to ZrTe 2 being a semimetal. The DFT calculations further suggest a band inversion between Te p and Zr d states at the Γ point, hinting at the nontrivial band topology in ZrTe 2 . Thus our studies suggest that ZrTe 2 is a topological semimetal. Also, a comparative band structure study is done on ZrSe 2 , which shows a semiconducting nature of the electronic structure with an indirect band gap of 0.9 eV between Γ ( A ) and M ( Lgical transition-metalMetal-chalcogen bond-length induced electronic phase transition from semiconductor to topological semimetal in Zr X 2 ( X = Se and Te)gical transition-metalMetal-chalcogen bond-length induced electronic phase transition from semiconductor to topological semimetal in Zr X 2 ( X = Se and Te) ) high-symmetry points. Below we show that the metal-chalcogen bond lengtgical transition-metalMetal-chalcogen bond-length induced electronic phase transition from semiconductor to topological semimetal in Zr X 2 ( X = Se and Te)h plays a critical role in the electronic phase transition from a semiconductor to a topological semimetal ingoing from ZrSe 2gical transition-metalMetal-chalcogen bond-length induced electronic phase transition from semiconductor to topological semimetal in Zr X 2 ( X = Se and Te) to ZrTe 2 .