Exchange striction driven magnetodielectric effect and potential photovoltaic effect in polar CaOFeS

Yang Zhang, Lingfang Lin, Jun-Jie Zhang, Xin Huang, Ming An, and Shuai Dong

Phys. Rev. Materials 1, 034406 – Published 30 August 2017

Abstract

CaOFeS is a semiconducting oxysulfide with a polar layered triangular structure. Here a comprehensive theoretical study has been performed to reveal its physical properties, including magnetism, electronic structure, phase transition, magnetodielectric effect, as well as optical absorption. Our calculations confirm the Ising-like G-type antiferromagnetic ground state driven by the next-nearest neighbor exchanges, which breaks the trigonal symmetry and is responsible for the magnetodielectric effect driven by exchange striction. In addition, a large coefficient of visible light absorption is predicted, which leads to promising photovoltaic effect with the maximum light-to-electricity energy conversion efficiency up to $24.2 %$ .