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Condensed Matter Seminar - "Quantum mechanics of 2D electron crystals"

Event Type
Seminar/Symposium
Sponsor
Physics - Condensed Matter
Location
ESB 190
Date
Oct 4, 2024   1:00 pm  
Speaker
Ilya Esterlis, University of Wisconsin, Madison
Contact
Stephen Bullwinkel
E-Mail
bullwink@illinois.edu
Phone
217-333-1652
Views
47
Originating Calendar
Physics - Condensed Matter Seminar

The low-carrier density state of a 2D semiconductor is described in terms of the homogeneous two-dimensional electron gas (2DEG), the ground state properties of which are determined by the electron density. Below a critical density, the electronic system freezes into a triangular lattice electron solid, or Wigner crystal. For experimentally relevant carrier concentrations the electron solid is highly quantum-mechanical, the significant overlap between localized electronic orbitals leading to frequent electron tunneling between Wigner crystal lattice sites. I will describe some new theoretical results exploring the consequences of these quantum effects in monolayer and bilayer 2DEG systems: In the monolayer case, increasing electron density may drive the Wigner crystal into a metallic charge-density wave state that can be understood as a quantum crystal with a finite concentration of itinerant ground-state defects, while in the bilayer case interlayer Coulomb interactions lead to new lattice geometries in which ring-exchange processes lead to a variety of interesting magnetic ground states. 

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