Twist-Induced Quantum Geometry Reconfiguration in Moir\'e Flat Bands

TL;DR

This paper demonstrates that twisting bilayer kagome lattices with loop-current order can significantly alter their quantum geometry, suppressing monolayer characteristics and enabling exploration of novel quantum phenomena in moiré flat bands.

Contribution

It reveals how twist-induced band reconstruction in loop-current kagome bilayers reconfigures quantum geometry, highlighting the role of strong interlayer hybridization and proposing new platforms for quantum material research.

Findings

Twist suppresses monolayer Berry curvature in kagome bilayers.

Interlayer hybridization reshapes quantum geometry.

Potential for experimental realization in vanadium-based kagome materials.

Abstract

The interplay between band topology, Berry curvature, and moir\'e flat bands lies at the heart of recent advances in quantum materials. In well-studied moir\'e systems such as twisted bilayer graphene and transition metal dichalcogenides, the quantum geometry of moir\'e flat bands typically reflects that of the monolayer, with Berry curvature originating from the band edge at the same valley. Whether this correspondence persists in systems with complex monolayer band structures and broken symmetries remains unclear. Here, we study twisted bilayers of loop-current-ordered kagome lattices (tb-LCK), which have been proposed in the context of vanadium-based kagome materials, using tight-binding models, and uncover a twist-induced reconfiguration of quantum geometry. By tuning the phase of the loop-current order, we identify the suppression of monolayer Berry curvature through twist-driven band reconstruction. We attribute these effects to strong interlayer hybridizations, enabled by the unusually large interlayer tunneling inherent to vanadium-based kagome materials, which mix energetically distant states and reshape quantum geometry. These results reveal that twist in tb-LCK suppresses quantum geometric inheritance from the monolayer, and establish loop-current-ordered moir\'e systems as promising platforms for exploring unconventional quantum geometry in moir\'e flat bands. We further comment on the experimental feasibility of the proposed system via vanadium-based kagome materials.