Edge magnetism in transition metal dichalcogenide nanoribbons: Mean field theory and determinant quantum Monte Carlo

TL;DR

This study investigates edge magnetism in transition metal dichalcogenide nanoribbons using mean field theory and quantum Monte Carlo, revealing filling-dependent magnetic phases and potential for spintronic applications.

Contribution

It combines mean field and determinant quantum Monte Carlo methods to analyze edge magnetism, highlighting the role of edge filling in magnetic phase stability and spin-polarized currents.

Findings

Antiferromagnetic gapped phase confirmed at specific edge filling.

Edge filling influences magnetic phases and edge currents.

Potential for tunable spintronic devices via back gate voltage.

Abstract

Edge magnetism in zigzag transition metal dichalcogenide nanoribbons is studied using a three-band tight-binding model with local electron-electron interactions. Both mean field theory and the unbiased, numerically exact determinant quantum Monte Carlo method are applied. Depending on the edge filling, mean field theory predicts different phases: gapped spin dimer and antiferromagnetic phases appear for two specific fillings, with a tendency towards metallic edge-ferromagnetism away from those fillings. Determinant quantum Monte Carlo simulations confirm the stability of the antiferromagnetic gapped phase at the same edge filling as mean field theory, despite being sign-problematic for other fillings. The obtained results point to edge filling as yet another key ingredient to understand the observed magnetism in nanosheets. Moreover, the filling dependent edge magnetism gives rise to spin-polarized edge currents in zigzag nanoribbons which could be tuned through a back gate voltage, with possible applications to spintronics.