title: Magnetic ordering and exchange striction stabilized geometric ferroelectricity in multiferroic AgCrS2.
abstract: The magnetic and ferroelectric properties of multiferroic AgCrS2 are investigated by the full potential linearized augmented plane wave method. For the low temperature crystal structure, the ground state is found to be in the collinear double ferromagnetic striped state with a [Formula: see text] spin structure, which is in good agreement with the neutron scattering result. The interlayer magnetic interactions are comparable to the intralayer ones, indicating that AgCrS2 is actually a three-dimensional frustrated antiferromagnet. Moreover, an analysis of Born effective charges and electric polarization reveals that the partial ferroelectricity in AgCrS2 belongs rather to the 'geometric ferroelectric' class, in which exchange striction and/or lattice distortion play an important role in stabilizing the polar structure.
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials and Faculty of Physics & Electronic Technology, Hubei University, Wuhan 430062, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Zhongbing
authors.initials: Z
authors.lastname: Huang
authors.forename: Ting
authors.initials: T
authors.lastname: Jia
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zeng