Theoretical study on electronic properties and pressure-induced phase transition in β-CdP 2

Abstract

In this paper, both the local density approximation (LDA) and the generalized gradient approximation (GGA) are used to investigate the structural and electronic properties of the β modification of CdP 2 ( β-CdP 2) at zero pressure. In addition, the energy band structure, electron density of states (DOS) and projected density of states (PDOS) analysis of β-CdP 2 are presented. What is more, we study the properties of β-CdP 2 in the pressure range of 0–20 GPa, show the variations of the cell volume and band gap with the pressure for both LDA and GGA approximation. Then, the bulk modulus B 0 and its first pressure derivative B 0 ′ obtained by fitting different equations of state (EOS) to the pressure–volume ( P– V) relation at ambient pressure are presented and compared with the available experimental data. At the end of our study, we for the first time find that a pressure-induced structural phase transition from the tetragonal phase ( β-CdP 2) to a orthorhombic phase (α-CdP 2) when the pressure is increased to a value between 20 and 25 Gpa in theory.