Emergence of topological defects and spin liquid in a two-orbital spin-fermion model on the honeycomb lattice

TL;DR

This study uses Monte Carlo simulations to demonstrate how orbital degeneracy and exchange interactions in a two-orbital spin-fermion model on a honeycomb lattice can induce topological defects and stabilize a spin liquid phase, revealing new pathways to realize spin liquids.

Contribution

It introduces a novel Monte Carlo approach to show how orbital effects and exchange interactions lead to spin liquid states on a honeycomb lattice, expanding understanding of quantum phase stabilization.

Findings

Suppression of magnetic orders via topological defects.

Emergence of a spin liquid phase between magnetic phases.

Tuning electron filling can induce phase transitions.

Abstract

Stabilizing exotic quantum phases of matter, e.g. spin liquid, is an attractive topic in condensed matter. Here, by a Monte Carlo study of a two-orbital spin-fermion model on a honeycomb lattice, we show the cooperative effects of the orbital degeneracy of itinerant electrons and the exchange interaction of localized spins can significantly suppress both ferromagnetic and antiferromagnetic orders by generating topological defects and give rise to an intermediate spin liquid state via continuous phase transitions. This phase competition can also be achieved by tuning the electron filling. These results shed new light on realizing spin liquids on geometrically non-frustrated lattices.