Elastoresistivity Signatures of Nematic Fluctuations in Layered Antiferromagnet CoTa3S6

TL;DR

This study investigates nematic fluctuations in CoTa3S6 using elastoresistivity, revealing a nematic degree of freedom intertwined with magnetic order, modulated by magnetic field and strain, with characteristic three-state nematicity signatures.

Contribution

It provides the first detailed elastoresistivity analysis of nematic fluctuations in CoTa3S6, demonstrating their coupling with magnetic order and identifying unique three-state nematicity signatures.

Findings

Nematic fluctuations diverge below the antiferromagnetic transition.

Nematicity is strongly modulated by magnetic field and strain.

Distinct three-state nematic signatures observed in magnetoresistance.

Abstract

Nematic phases that break rotational symmetry are widely observed in quantum materials, and clarifying their origin and relationship with other symmetry-breaking phases remains an important but challenging task. In this work, we investigate nematic fluctuations in CoTa$_3$S$_6$ using elastoresistivity experiments to resolve the nature of the proposed nematic phase intertwined with collinear and non-coplanar antiferromagnetic orders. We observe a divergence-like antisymmetric elastoresistivity that rapidly develops below the stripe antiferromagnetic transition, consistent with a distinct nematic degree of freedom coupled to the magnetic order. While nematic fluctuations are strongly modulated by an external out-of-plane magnetic field and the onset temperature of resistivity anisotropy shows pronounced strain dependence, the antiferromagnetic transition temperatures remain nearly unchanged under either magnetic field or strain. Additionally, complementary magnetoresistance measurements reveal characteristic signatures of three-state nematicity in a hexagonal system. Our findings demonstrate CoTa$_3$S$_6$ as a unique case of intertwined nematic and AFM orders with distinct origins.