Presence of x-ray magnetic circular dichroism effect for zero-magnetization state in antiferromagnetism

TL;DR

This paper demonstrates the theoretical presence of an XMCD signal in antiferromagnetic Kagome lattice structures, linking the signal to spin chirality and sublattice charge anisotropies, challenging the typical absence of XMCD in AFM states.

Contribution

It introduces a theoretical model showing XMCD signals in compensated AFM structures based on spin chirality and sublattice properties, which is a novel insight.

Findings

XMCD signal appears in AFM Kagome lattice structures.

XMCD correlates with the sign of spin chirality.

Differences in charge density anisotropies cause the XMCD signal.

Abstract

X-ray magnetic circular dichroism (XMCD) is generally not observed for antiferromagnetic (AFM) states because XMCD signals from the antiparallelly coupled spins cancel each other. In this letter, we theoretically show the presence of an XMCD signal from compensated two-dimensional triangle AFM structures on a Kagome lattice. The calculation reveals the complete correspondence between the XMCD spectra and the sign of the spin chirality: the XMCD signal only appears when the spin chirality is negative. This XMCD signal originates from the different absorption coefficients of the three sublattices reflecting different charge density anisotropies and directions of spin and orbital magnetic moments.