Spinon pairing induced by chiral in-plane exchange and the stabilization of odd-spin Chern number spin liquid in twisted ${\mathrm{MoTe}}_2$

Abstract

The unusual structure and symmetry of low-energy states in twisted transition metal dichalcogenides leads to large in-plane spin-exchange interactions between spin-valley locked holes. We demonstrate that this exchange interaction can stabilize a gapped spin-liquid phase with a quantized spin-Chern number of three when the twist angle is sufficiently small and the system lies in a Mott insulating phase. The gapped spin liquid may be understood as arising from spinon pairing in the DIII Altland-Zirnbauer symmetry class. Applying an out of plane electric field or increasing the twist angle is shown to drive a transition respectively to an anomalous Hall insulator or an in-plane antiferromagnet. Recent experiments indicate that a spin-Chern number three phase occurs in twisted MoTe${}_2$ at small twist angles with a transition to a quantum anomalous Hall phase as the twist angle is increased above a critical value of about $2.5^{\circ }$ in absence of applied electric field.

References in corpus (6)

• Introduction to topological superconductivity and Majorana fermions
• Signatures of Fractional Quantum Anomalous Hall States in Twisted MoTe2 Bilayer
• Observation of Fractionally Quantized Anomalous Hall Effect
• Quantum Spin Hall Effect and Topologically Invariant Chern Numbers
• Observation of integer and fractional quantum anomalous Hall effects in twisted bilayer MoTe2
• Topological aspects of quantum spin Hall effect in graphene: Z${}_2$ topological order and spin Chern number