Stability of spontaneous quantum Hall state in the Triangular Kondo-lattice model

TL;DR

This paper investigates the stability of a spontaneous quantum Hall state in a quarter-filled Kondo lattice model on a triangular lattice, revealing a phase transition to an exotic spin order with quantum Hall effect.

Contribution

It combines variational and Monte Carlo methods to demonstrate a thermodynamic phase transition into a spin-ordered state with spontaneous quantum Hall effect in the model.

Findings

Identification of a phase transition to a spin-ordered state with scalar spin chirality.

Observation of spontaneous quantum Hall effect without external magnetic field.

Analysis of external magnetic field effects on the quantum Hall state.

Abstract

We study the behavior of the quarter-filled Kondo lattice model on a triangular lattice by combining a zero-temperature variational approach and finite-temperature Monte-Carlo simulations. For intermediate coupling between itinerant electrons and classical moments ${\bf S}_j$, we find a thermodynamic phase transition into an exotic spin ordering with uniform scalar spin chirality and $< {\bf S}_j >=0$. The state exhibits spontaneous quantum Hall effect. We also study how its properties are affected by application of an external magnetic field.