Structure, bonding nature and transition dynamics of amorphous Te

Abstract

Te has drawn many interest due to the excellent electrical and optical performances in both bulk and 2D scale. Although amorphous phase usually generates some particular characteristics, relevant studies are still inadequate. By using ab initio molecular dynamics (AIMD) simulations, we have explored the dynamics and structure of Te during amorphization process. The large fraction of 2- and 3-coordinated Te results in an average coordination number of 2.43 in amorphous Te (a-Te), deviating from the “8-N rule”. The 2-coordinated chain structures and the 3- and 4-coordinated defective octahedral clusters, together with 25.3% voids, make a-Te a flexible and fragile glass. As a result, a mid-gap state is observed in the electronic density of states. Our study deepens the insight on a-Te, which is useful for the design of novel electronic and optical devices.