Tue October 27, 2020 4:00 pm

Virtual CUA Seminar – Signatures of bilayer Wigner crystals in an atomically thin heterostructure


A Wigner crystal is one of the earliest predicted collective electronic states and exhibits intriguing quantum and classical phase transitions. However, the realization of quantum Wigner crystals often requires placing semiconductors in a strong magnetic field, which limits the detailed interrogation of these correlated states and their phase transitions. In this talk, I will present a new platform to realize Wigner crystals without a magnetic field, based on atomically thin heterostructures made of transition metal dichalcogenides [1]. In particular, we create semiconducting MoSe2 bilayers separated by a thin insulating layer and electrically control the individual layer’s carrier density. We observe optical signatures of a series of bilayer Wigner crystals formed at symmetric (1:1) and asymmetric (4:1 and 7:1) electron doping of the two MoSe2 layers. These bilayer Wigner crystals, created from the commensurate stacking of triangular electron lattices, are remarkably stable and allow us to probe both quantum and classical melting transitions in the system. Our results open up new avenues for creating, investigating, and controlling exotic many-body quantum phases and their phase transitions.

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