title: Rigorous determination of the ground-state phases and thermodynamics in an Ising-type multiferroic chain.
abstract: To understand the ferroelectricity driven by collinear magnetism in a multiferroic spin-chain system, we have adopted an elastic diatomic Ising spin-chain model with axial next-nearest-neighbor interaction to describe its magnetoelectric properties. By employing magneto-phonon decoupling and the transfer-matrix method, the possible ground-state configurations and thermodynamic behaviors of the system have been determined exactly. The parameter relation for the appearance of electric polarization has been discussed from the perspective of the ground-state configuration. In the case of nearest-neighbor antiferromagnetic coupling, a novel series of zero-temperature transitions induced by magnetic field have been observed, from the ↑↑↓↓ spin configuration associated with ferroelectric order to the ↑↓↑ state with a peculiar 1/3 magnetization plateau, then to the ↑↑↑↓ state, and finally saturation in the ↑↑↑↑ state.
authors.affiliation: School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qi
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.forename: Nai-sen
authors.initials: NS
authors.lastname: Yu
authors.forename: An
authors.initials: A
authors.lastname: Du