Spin-orbital magnetism in moir\'e Wigner molecules

TL;DR

This paper proposes a new platform using moiré Wigner molecules in TMD materials to realize and study tunable spin-orbital interactions, revealing a diverse phase diagram of correlated phases.

Contribution

It introduces a tunable spin-orbital Hamiltonian in moiré TMDs based on Wigner molecules, expanding the possibilities for correlated quantum phases.

Findings

Moiré TMDs can host a general, tunable spin-orbital Hamiltonian.

The phase diagram includes ferri-electric valence bond solids and a helical spin liquid.

The platform enables exploration of diverse correlated spin-orbital phenomena.

Abstract

The interplay of spin and orbital degrees of freedom offers a versatile playground for the realization of a variety of correlated phases of matter. However, the types of spin-orbital interactions are often limited and challenging to tune. Here, we propose and analyze a new platform for spin-orbital interactions based upon a lattice of Wigner molecules in moir\'e transition metal dichalcogenides (TMDs). Leveraging the spin-orbital degeneracy of the low-energy Hilbert space of each Wigner molecule, we demonstrate that TMD materials can host a general spin-orbital Hamiltonian that is tunable via the moir\'e superlattice spacing and dielectric environments. We study the phase diagram for this model, revealing a rich landscape of phases driven by spin-orbital interactions, ranging from ferri-electric valence bond solids to a helical spin liquid. Our work establishes moir\'e Wigner molecules in TMD materials as a prominent platform for correlated spin-orbital phenomena.