ELECTRONIC AND ELASTIC PROPERTIES OF CrO2 IN THE ORTHORHOMBIC CaCl2-TYPE STRUCTURE

Abstract

The structure, electronic and elastic properties of CrO 2 in the high pressure orthorhombic CaCl 2 (Pnnm) phase are investigated by first-principles calculations based on density functional theory (DFT). Our calculated crystal parameters are in good agreement with the available experimental data. The electronic band structure, density of state (DOS) and projected density of state (PDOS) at 14 GPa are studied within local spin density approximation (LSDA) and generalized gradient approximation (GGA) in details. The CaCl 2 phase of CrO 2 still has the half metal character, which is in accordance with previous theoretical predictions. The elastic constants, bulk modulus, shear modulus, Young's modulus and Poisson ratio under pressures are successfully obtained for the orthorhombic CaCl 2 phase of CrO 2. This structure is mechanically stable at our applied range of pressures. The calculated elastic anisotropic factors show that the CaCl 2 phase of CrO 2 is provided with high elastic anisotropy and the elastic anisotropy decreases with increasing pressures. The propagation speed of transverse, longitudinal elastic wave together with associated Debye temperatures are also estimated.