Spin Vortex Crystal Order in Organic Triangular Lattice Compound

TL;DR

This paper reports the discovery of spin-vortex crystal order in the organic compound -(BETS)2Mn[N(CN)2]3, providing experimental evidence for ring-exchange effects and supporting the chiral spin-liquid scenario in triangular lattice organics.

Contribution

It presents experimental identification of spin-vortex crystal order in a new organic compound, confirming theoretical predictions about ring-exchange and chiral magnetic states.

Findings

Identification of spin-vortex crystal order via measurements and calculations

Confirmation of ring-exchange's role in stabilizing magnetic order

Support for chiral spin-liquid scenario in triangular lattice organics

Abstract

Organic salts represent an ideal experimental playground for studying the interplay between magnetic and charge degrees of freedom, which has culminated in the discovery of several spin-liquid candidates, such as $\kappa$-(ET)$_2$Cu$_2$(CN)$_3$ ($\kappa$-Cu). Recent theoretical studies indicate the possibility of chiral spin liquids stabilized by ring-exchange, but the parent states with chiral magnetic order have not been observed in this material family. In this work, we discuss the properties of the recently synthesized $\kappa$-(BETS)$_2$Mn[N(CN)$_2$]$_3$ ($\kappa$-Mn). Based on analysis of specific heat, magnetic torque, and NMR measurements combined with ab initio calculations, we identify a spin-vortex crystal order. These observations definitively confirm the importance of ring-exchange in these materials, and support the proposed chiral spin-liquid scenario for triangular lattice organics.