Crystallizing electrons with artificially patterned lattices

Abstract

Wigner crystals are typically confined to ultralow temperatures where thermal motion is frozen out. Moiré superlattices in twisted two-dimensional materials have extended their stability to higher temperatures and densities, but rely on delicate stacking that fixes the lattice geometry and limits tunability. Here we demonstrate a lithographic approach that bypasses these constraints. Using high-resolution nanofabrication, we pattern a nanoscale triangular lattice directly into a graphene gate integrated with a monolayer MoSe2 semiconductor. This engineered potential landscape localizes electrons into generalized Wigner crystal states that persist up to 15 K and densities of 2X10^12 cm-2, representing an order of magnitude improvement over pristine monolayer MoSe2. Gate-voltage control allows real-time switching between stable and unstable crystalline states, with the latter exhibiting stochastic telegraph noise from nearly degenerate configurations. This work demonstrates the ability of this platform to transform Wigner crystals from fragile, static phases into reconfigurable quantum matter.

References in corpus (19)

• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Moire bands in twisted double-layer graphene
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Optical detection of Mott and generalized Wigner crystal states in WSe2/WS2 moiré superlattices
• Signatures of Fractional Quantum Anomalous Hall States in Twisted MoTe2 Bilayer
• Abundance of correlated insulating states at fractional fillings of WSe${}_2$/WS${}_2$ moiré superlattices
• Signatures of bilayer Wigner crystals in a transition metal dichalcogenide heterostructure
• Observation of Wigner crystal of electrons in a monolayer semiconductor
• Band Structure Engineering of 2D Materials using Patterned Dielectric Superlattices
• Phase Diagram of the Low-Density Two-Dimensional Homogeneous Electron Gas
• Realization of an atomically thin mirror using monolayer MoSe2
• Optical properties of graphene antidot lattices
• Generalized Wigner crystallization in moiré materials
• Shubnikov-de Haas oscillations in optical conductivity of monolayer MoSe${}_2$
• Nanoscale trapping of interlayer excitons in a 2D semiconductor heterostructure
• Confined Trions and Mott-Wigner States in a Purely Electrostatic Moiré Potential
• Noise and Thermal Depinning of Wigner Crystals
• Single exciton trapping in an electrostatically defined 2D semiconductor quantum dot
• Excitons in periodic potentials