Majorana zero modes in twisted transition metal dichalcogenides homobilayers

TL;DR

This paper explores the rich phase diagram of twisted transition metal dichalcogenide homobilayers, predicting Majorana zero modes in a tunable platform that combines topological insulators and superconductivity without external magnetic fields.

Contribution

It introduces a novel, electrically tunable platform using semiconductor moiré homobilayers to realize Majorana zero modes without external magnetic fields.

Findings

Multiple quantum phases identified, including quantum spin Hall and various magnetic states.

Prediction of a gate-defined junction hosting Majorana zero modes.

Proposal of a magnetic-field-free topological superconductor platform.

Abstract

Semiconductor moir\'e superlattices provide a highly tunable platform to study the interplay between electron correlation and band topology. For example, the generalized Kane-Mele-Hubbard model can be simulated by the topological moir\'e flat bands in twisted transition metal dichalcogenides homobilayers. For this system, we obtain the filling factor, twist angle, and electric field-dependent quantum phase diagrams with a plethora of phases, including the quantum spin Hall insulator, the in-plane antiferromagnetic state, the out-of-plane antiferromagnetic Chern insulator, the spin-polarized Chern insulator, the in-plane ferromagnetic state, and the 120$^\circ$ antiferromagnetic state. We predict that a gate-defined junction formed between the quantum spin Hall insulator phase with proximitized superconductivity and magnetic phases with in-plane magnetization (either ferromagnetic or antiferromagnetic) can realize one-dimensional topological superconductor with Majorana zero modes. Our proposal introduces semiconductor moir\'e homobilayers as an electrically tunable Majorana platform with no need of an external magnetic field.