Observation of {\Gamma}-valley moir\'e bands and emergent hexagonal lattice in twisted transition metal dichalcogenides

TL;DR

This study reveals that in twisted bilayer WSe2, moiré bands are observed only at the { extGamma}-valley, leading to emergent honeycomb and Kagome lattice charge distributions, highlighting a new platform for correlated physics.

Contribution

The paper demonstrates the existence of { extGamma}-valley moiré bands in twisted bilayer WSe2 and their association with emergent honeycomb and Kagome charge lattices, revealing valley-dependent electronic structures.

Findings

Moiré bands observed only at { extGamma}-valley, not at K-valley.

Real-space charge distributions form honeycomb and Kagome patterns.

{ extGamma}-valley moiré bands are promising for strongly correlated physics.

Abstract

Twisted van der Waals heterostructures have recently been proposed as a condensed-matter platform for realizing controllable quantum models due to the low-energy moir\'e bands with specific charge distributions in moir\'e superlattices. Here, combining angle-resolved photoemission spectroscopy with sub-micron spatial resolution ({\mu}-ARPES) and scanning tunneling microscopy (STM), we performed a systematic investigation on the electronic structure of 5.1{\deg} twisted bilayer WSe2 that hosts correlated insulating and zero-resistance states. Interestingly, contrary to one's expectation, moir\'e bands were observed only at {\Gamma}-valley but not K-valley in {\mu}-ARPES measurements; and correspondingly, our STM measurements clearly identified the real-space honeycomb- and Kagome-shaped charge distributions at the moir\'e length scale associated with the {\Gamma}-valley moir\'e bands. These results not only reveal the unsual valley dependent moir\'e-modified electronic structure in twisted transition metal dichalcogenides, but also highlight the {\Gamma}-valley moir\'e bands as a promising platform for exploring strongly correlated physics in emergent honeycomb and Kagome lattices at different energy scales.