Influence of lattice distortions in classical spin systems

Abstract

We investigate a simple model of a frustrated classical spin chain coupled to adiabatic phonons under an external magnetic field. A thorough study of the magnetization properties is carried out both numerically and analytically. We show that already a moderate coupling with the lattice can stabilize a plateau at 1/3 of the saturation and discuss the deformation of the underlying lattice in this phase. We also study the transition to saturation where either a first or second order transition can occur, depending on the couplings strength.Comment: Submitted to Phys. Rev.

Magnetization process in the classical Heisenberg model on the Shastry-Sutherland lattice

“…Furthermore, magnetic anisotropies are also expected to be important for the rare-earth tetraborides. 16,17,18,19,20,21,22 Finally, it has been observed on some other lattices 49,50,51 that coupling to phonons leads to a stabilization of magnetization plateaux. It would therefore be interesting to study the classical Heisenberg model coupled to lattice degrees of freedom also on the Shastry-Sutherland lattice.…”

Topological solitons and bulk polarization switch in collinear type-II multiferroics

“…This has been studied not only in one dimensional spin chains but also in higher dimensions [63][64][65][66][67]. The spinlattice coupling also provides mechanisms for the opening of plateaus at different magnetization fractions, either for quantum S = 1/2 spins [68] or classical spins [69].…”

Lattice distortions in a sawtooth chain with Heisenberg and Ising bonds

“…Here the sum is over all values of Ising variables and Sp S stands for the trace over all states of quantum spins, for each quantum bond there is also integral over all possible values of distortion. After implementing integration, one arrives at the effective Hamiltonian with additional bi-quadratic term, which is widely used in the investigations of spin systems with adiabatic coupling to phonons [1][2][3][4][5][6][7] . Then, trace over quantum states can be taken independently for each block, yielding…”

“…The lift of the ground state degeneracy in frustrated magnets and magnetization plateaus stabilization mechanisms have been investigated intensively in various lattice spin systems with spin-lattice coupling [1][2][3][4][5][6] . The concept of adiabatic phonos 7 yielding the effective spin Hamiltonian with additional biquadratic interaction is one of the main approximations using to gain inside into the properties of strongly correlated spin systems, interacting with lattice vibrations.…”