Structural and Electronic Properties of Orthorhombic Phase Bi2Se3 Based on First-Principles Study

Abstract

Bi₂Se₃ is one of the promising materials in thermoelectric devices and is environmentally friendly due to its efficiency to perform in room temperature. Structural and electronic properties of Bi₂Se₃ were investigated based on the first-principles calculation of density functional theory (DFT) using CASTEP computer code. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalised gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. A comparative study is carried out between the electronic properties of LDA and GGA-PBE. Lattice parameter and band gap are consistent with the other reports. Calculation from LDA is more accurate and has a better agreement than GGA-PBE in describing the lattice parameter of Bi₂Se₃. Band gap and density of states of LDA show higher electrical conductivity than GGA-PBE. Both LDA and GGA-PBE have same degree of thermal conductivity due to the occurrence of indirect band gap at same range of wave vector.