Quantum melting of generalized electron crystal in twisted bilayer MoSe2

TL;DR

This paper reports the electrical transport detection of generalized Wigner crystals in twisted bilayer MoSe2 and observes their quantum melting transitions to liquid phases under various tuning parameters.

Contribution

It provides the first electrical transport evidence of GWCs in twisted bilayer MoSe2 and characterizes their quantum melting behavior.

Findings

Detection of GWCs at multiple fractional fillings.

Observation of continuous quantum melting transitions.

Identification of quantum critical scaling behaviors.

Abstract

Electrons can form an ordered solid crystal phase ascribed to the interplay between Coulomb repulsion and kinetic energy. Tuning these energy scales can drive a phase transition from electron solid to liquid, i.e. melting of Wigner crystal. Generalized Wigner crystals (GWCs) pinned to moire superlattices have been reported by optical and scanning-probe-based methods. Using transport measurements to investigate GWCs is vital to a complete characterization, however, still poses a significant challenge due to difficulties in making reliable electrical contacts. Here, we report the electrical transport detection of GWCs at fractional fillings nu = 2/5, 1/2, 3/5, 2/3, 8/9, 10/9, and 4/3 in twisted bilayer MoSe2. We further observe that these GWCs undergo continuous quantum melting transitions to liquid phases by tuning doping density, magnetic and displacement fields, manifested by quantum critical scaling behaviors. Our findings establish twisted bilayer MoSe2 as a novel system to study strongly correlated states of matter and their quantum phase transitions.