Magneto-elastic effects and magnetization plateaus in two dimensional systems

TL;DR

This paper investigates how strong frustration and spin-lattice coupling influence magnetization plateaus in two-dimensional frustrated spin systems, revealing complex spin textures and lattice distortions that can be experimentally observed.

Contribution

It demonstrates the stabilization of magnetization plateaus with complex unit cells in a frustrated spin-1/2 Heisenberg model coupled to phonons, highlighting the role of spin-lattice interactions.

Findings

Stabilization of simple structures at zero magnetization

Formation of larger unit cells with non-trivial spin textures at half magnetization

Predictions of lattice distortions measurable by X-ray and NMR

Abstract

We show the importance of both strong frustration and spin-lattice coupling for the stabilization of magnetization plateaus in translationally invariant two-dimensional systems. We consider a frustrated spin-1/2 Heisenberg model coupled to adiabatic phonons under an external magnetic field. At zero magnetization, simple structures with two or at most four spins per unit cell are stabilized, forming dimers or $2 \times 2$ plaquettes, respectively. A much richer scenario is found in the case of magnetization $m=1/2$, where larger unit cells are formed with non-trivial spin textures and an analogy with the corresponding classical Ising model is detectable. Specific predictions on lattice distortions and local spin values can be directly measured by X-rays and Nuclear Magnetic Resonance experiments.