Year: 2025
Type: article
Abstract: The recent discovery of topological flat bands in twisted transition metal dichalcogenide homobilayers and multilayer graphene has sparked significant research interest. Here, a new platform for realizing tunable topological moiré flat bands: twisted type‐II Rashba homobilayers, is proposed. By maintaining centrosymmetry, the interplay between Rashba spin‐orbit coupling and interlayer interactions generates an effective pseudo‐antiferromagnetic field, opening a gap within the Dirac cone with non‐zero Berry curvature. Using twisted BiTeI bilayers as an example, it is predicted that the emergence of flat topological bands with a remarkably narrow bandwidth (below 20 meV). Notably, the system undergoes a transition from a valley Hall insulator to a quantum spin Hall insulator as the twisting angle increases. This transition arises from a competition between the twisting‐driven effective spin‐orbit coupling and sublattice onsite energies presented in type‐II Rashba moiré structures. The high tunability of Rashba materials in terms of the spin‐orbit coupling strength, interlayer interaction, and twisting angle expands the range of materials suitable for functionalizing and manipulating correlated topological properties.
Source: Advanced Functional Materials
Authors: Xilong Xu, Haonan Wang, Li Yang
Institution: Washington University in St. Louis
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1453181110, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G2299875479, Collaborative Research: DMREF: Accelerated Discovery of Artificial Multiferroics with Enhanced Magnetoelectric Coupling, G2888034965, G3146600022, G3166468702, G3185749182, G3406661761, G3562386289, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4010157413, G4508537685, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5212984984, G5367127336, G5464919783, G5673570383, G5911616549, G6121277264, G6965887028, G731264315, G749531909, Doping Effects on Excited-State Properties of Two-Dimensional Moiré Crystals, G8174472116, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, G878072758, G9000146395
OpenAlex ID: W4410035792