Multifunctional Antiperovskites driven by Strong Magnetostructural Coupling

TL;DR

This study uses density functional theory to explore the multifunctional properties of cubic antiperovskites, revealing strong magnetostructural coupling, strain-tunable spintronic effects, and potential applications in thermal and magnetic devices.

Contribution

It identifies specific stable antiperovskites with noncollinear magnetic states driven by frustrated exchange and anisotropy, and demonstrates strain effects on their electronic and magnetic properties.

Findings

16 out of 54 stable antiperovskites exhibit antiferromagnetic configurations.

Paramagnetic state is key to understanding negative thermal expansion.

Strain can significantly tune anomalous Hall/Nernst conductivities.

Abstract

Based on density functional theory calculations, we elucidated the origin of multifunctional properties for cubic antiperovskites with noncollinear magnetic ground states, which can be attributed to strong isotropic and anisotropic magnetostructural coupling. 16 out of 54 stable magnetic antiperovskites M$_3$XZ (M = Cr, Mn, Fe, Co, and Ni; X = selected elements from Li to Bi except for noble gases and 4f rare-earth metals; and Z = C and N) are found to exhibit the $\Gamma_{4g}$/$\Gamma_{5g}$ (i.e., characterized by irreducible representations) antiferromagnetic magnetic configurations driven by frustrated exchange coupling and strong magnetocrystalline anisotropy. Using the magnetic deformation as an effective proxy, the isotropic magnetostructural coupling is characterized, and it is observed that the paramagnetic state is critical to understand the experimentally observed negative thermal expansion and to predict the magnetocaloric performance. Moreover, the piezomagnetic and piezospintronic effects induced by biaxial strain are investigated. It is revealed that there is not a strong correlation between the induced magnetization and anomalous Hall conductivities by the imposed strain. Interestingly, the anomalous Hall/Nernst conductivities can be significantly tailored by the applied strain due to the fine-tuning of the Weyl points energies, leading to promising spintronic applications.