Light driven magnetic transitions in transition metal dichalcogenide heterobilayers

TL;DR

This paper explores how different types of light can be used to control and induce magnetic phase transitions in twisted transition metal dichalcogenide heterobilayers, offering a new way to manipulate quantum states.

Contribution

It introduces a method to use waveguide and circularly polarized light to dynamically control magnetic phases in TMD heterobilayers, expanding the toolkit for Floquet engineering.

Findings

Waveguide light can modulate interlayer hoppings and induce magnetic phase transitions.

Circularly polarized light alters the effective mass of TMD layers.

Combined light sources enable in-situ control of the phase diagram.

Abstract

Motivated by the recent excitement around the physics of twisted transition metal dichalcogenide (TMD) multilayer systems, we study strongly correlated phases of TMD heterobilayers under the influence of light. We consider both waveguide light and circularly polarized light. The former allows for longitudinally polarized light, which in the high frequency limit can be used to selectively modify interlayer hoppings in a tight-binding model. We argue based on quasi-degenerate perturbation theory that changes to the interlayer hoppings can be captured as a modulation to the strength of the moir\'e potential in a continuum model. As a consequence, waveguide light can be used to drive transitions between a myriad of different magnetic phases, including a transition from a $120^\circ$ Neel phase to a stripe ordered magnetic phase, or from a spin density wave phase to a paramagnetic phase, among others. When the system is subjected to circularly polarized light we find that the effective mass of the active TMD layer is modified by an applied electromagnetic field. By simultaneously applying waveguide light and circularly polarized light to a system, one has a high level of control in moving through the phase diagram in-situ. Lastly, we comment on the experimental feasibility of Floquet state preparation and argue that it is within reach of available techniques when the system is coupled to a judiciously chosen bath.