Direct observation of distinct minibands in moir\'e superlattices

TL;DR

This study uses advanced ARPES techniques to observe and analyze miniband formation in a range of moiré superlattices with varying wavelengths, revealing new insights into their electronic structures and potential for engineering layered quantum materials.

Contribution

It provides direct experimental observation of minibands in short-wavelength moiré superlattices and demonstrates the ability to imprint large moiré potentials on separate layers.

Findings

Observation of minibands in superlattices with wavelengths as short as 0.5 nm

Detection of distinct dispersions caused by moiré potentials

Large moiré potential imprinting on a third layer in heterostructures

Abstract

Moir\'e superlattices comprised of stacked two-dimensional materials present a versatile platform for engineering and investigating new emergent quantum states of matter. At present, the vast majority of investigated systems have long moir\'e wavelengths, but investigating these effects at shorter, incommensurate wavelengths, and at higher energy scales, remains a challenge. Here, we employ angle-resolved photoemission spectroscopy (ARPES) with sub-micron spatial resolution to investigate a series of different moir\'e superlattices which span a wide range of wavelengths, from a short moir\'e wavelength of 0.5 nm for a graphene/WSe2 (g/WSe2) heterostructure, to a much longer wavelength of 8 nm for a WS2/WSe2 heterostructure. We observe the formation of minibands with distinct dispersions formed by the moir\'e potential in both systems. Finally, we discover that the WS2/WSe2 heterostructure can imprint a surprisingly large moir\'e potential on a third, separate layer of graphene (g/WS2/WSe2), suggesting a new avenue for engineering moir\'e superlattices in two-dimensional materials.