Large spin-phonon coupling and magnetically-induced phonon anisotropy in Sr$M$O$_3$ perovskites ($M$=V,Cr,Mn,Fe,Co)

TL;DR

This study uses first-principles calculations to reveal significant spin-phonon coupling and phonon anisotropy in Sr$M$O$_3$ perovskites, showing magnetic order strongly influences phonon properties and phase behavior.

Contribution

It demonstrates large spin-phonon coupling in Sr$M$O$_3$ perovskites and models its dependence on magnetic order using a crystal-structure-dependent Heisenberg framework.

Findings

Frequency and splitting of polar modes depend on magnetic order.

Coupling leads to potential phase transitions driven by external stimuli.

Magnetic, structural, and electronic phases are interconnected.

Abstract

First-principles calculations reveal large zone-center spin-phonon coupling and magnetically-driven phonon anisotropy in cubic perovskites Sr$M$O$_3$ ($M$=V,Cr,Mn,Fe,Co). In particular, the frequency and splitting of the polar Slater mode is found to depend strongly on magnetic ordering. The coupling is parameterized in a crystal-structure-dependent Heisenberg model and its main features seen to arise from the Goodenough-Kanamori rules. This coupling can be expected to produce distinct low-energy alternative phases, resulting in a rich variety of coupled magnetic, structural and electronic phase transitions driven by temperature, stress, electric field and cation substitution.