Noncollinear antiferromagnetic structure and physical properties of CrRhAs with distorted kagome lattice

TL;DR

This study experimentally investigates CrRhAs, revealing its noncollinear antiferromagnetic structure, anomalous transport properties, and strong electronic correlations, advancing understanding of kagome metals.

Contribution

First experimental determination of CrRhAs's magnetic structure and physical properties, highlighting deviations from theoretical predictions and uncovering complex electronic behavior.

Findings

CrRhAs has a noncollinear antiferromagnetic structure with propagation vector (1/3, 1/3, 1/2).

CrRhAs exhibits semiconducting-like resistivity above TN and metallic below TN.

Hall coefficients show two sign changes, indicating multiband effects.

Abstract

CrRhAs was theoretically proposed to be a kagome metal with unusual magnetic ground states; however, little is known about its magnetic structure and physical properties experimentally. Here, we present an experimental investigation of CrRhAs with ZrNiAl-type structure and a distorted Cr kagome lattice. CrRhAs is an antiferromagnet with TN = 149 K. Powder neutron diffraction analysis reveals a noncollinear antiferromagnetic structure with propagation vector k = (1/3, 1/3, 1/2), which features a ferromagnetic second nearest neighbor coupling in the kagome plane that is different from the prediction in previous density functional theory calculations. Furthermore, CrRhAs exhibits anomalous electrical transport properties which are possibly related to multiband effects and strong spin fluctuations. For the temperature-dependent longitudinal resistivity \r{ho}xx, it is semiconductinglike above TN and becomes metallic below TN . The Hall coefficients exhibit two sign changes near 70 and 300 K. Combined with the results of heat capacity measurements, a large Kadowaki-Woods ratio {\alpha} = 33.9 {\mu}{\Omega} cm mol2 K2/J2 is obtained. The above results suggest CrRhAs is a strongly correlated kagome metal with multiband and noncollinear magnetic structure features.