Anomalous Spin Response in Non-centrosymmetric Compounds

TL;DR

This paper investigates the unusual momentum-dependent spin susceptibilities in non-centrosymmetric tetragonal compounds, revealing enhancements due to Coulomb interactions and proposing neutron scattering as a probe.

Contribution

It provides a group theoretical explanation for the anomalous spin susceptibilities and suggests a polarized neutron scattering experiment to detect these effects.

Findings

Anomalous momentum dependences of spin susceptibilities are identified.

Coulomb interactions enhance the magnitude of these susceptibilities.

A polarized neutron scattering experiment is proposed as a direct probe.

Abstract

We examine static spin susceptibilities $\chi_{\alpha\beta}({\bf q})$ of spin components $S_{\alpha}$ and $S_{\beta}$ in the non-centrosymmetric tetragonal system. These show anomalous momentum dependences like $\chi_{xx}({\bf q})-\chi_{yy}({\bf q})\sim q_x^2-q_y^2$ and $\chi_{xy}({\bf q})+\chi_{yx}({\bf q})\sim q_x q_y$, which vanish in centrosymmetric systems. The magnitudes of the anomalous spin susceptibilities are enhanced by the on-site Coulomb interaction, especially, around an ordering wave vector. The significant and anomalous momentum dependences of these susceptibilities are explained by a group theoretical analysis. As the direct probe of the anomalous spin susceptibility, we propose a polarized neutron scattering experiment.