Frustration-induced insulating chiral spin state in itinerant triangular-lattice magnets

TL;DR

This paper investigates a double-exchange model on a triangular lattice, revealing a robust scalar-chiral insulating spin state that emerges between ferromagnetic and Yafet-Kittel phases, with notable transport anomalies at finite temperatures.

Contribution

It introduces a new scalar-chiral insulating spin state in a frustrated itinerant magnet model, combining numerical methods to explore its properties.

Findings

Scalar-chiral insulating state emerges between ferromagnetic and Yafet-Kittel phases.

Finite temperature behavior shows anomalous bad-metal transport.

The state is robust and relevant to frustrated itinerant magnets like R$_2$Mo$_2$O$_7$.

Abstract

We study the double-exchange model at half-filling with competing superexchange interactions on a triangular lattice, combining exact diagonalization and Monte-Carlo methods. We find that in between the expected itinerant ferromagnetic and $120^{\circ}$ Yafet-Kittel phases a robust scalar-chiral, insulating spin state emerges. At finite temperatures the ferromagnet - scalar-chiral quantum critical point is characterized by anomalous bad-metal behavior in charge transport as observed in frustrated itinerant magnets R$_2$Mo$_{2}$O$_7$.