Coupled spin-lattice dynamics from the tight-binding electronic structure

TL;DR

This paper introduces a computationally efficient method for simulating coupled spin and lattice dynamics based on tight-binding electronic structure, capturing complex interactions beyond traditional Hamiltonian models.

Contribution

The authors develop a novel approach that integrates adiabatic spin and lattice dynamics from a tight-binding model, surpassing the accuracy of parameterized Hamiltonians and reducing computational costs.

Findings

Lattice dynamics are significantly affected by magnetic configurations.

Disorder can induce notable lattice distortions.

The method is more efficient than ab initio approaches.

Abstract

We developed a method which performs the coupled adiabatic spin and lattice dynamics based on the tight-binding electronic structure model, where the intrinsic magnetic field and ionic forces are calculated from the converged self-consistent electronic structure at every time step. By doing so, this method allows us to explore limits where the physics described by a parameterized spin-lattice Hamiltonian is no longer accurate. We demonstrate how the lattice dynamics is strongly influenced by the underlying magnetic configuration, where disorder is able to induce significant lattice distortions. The presented method requires significantly less computational resources than ab initio methods, such as time-dependent density functional theory (TD-DFT). Compared to parameterized Hamiltonian-based methods, it also describes more accurately the dynamics of the coupled spin and lattice degrees of freedom, which becomes important outside of the regime of small lattice and spin fluctuations.