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
- bullwink@illinois.edu
- Phone
- 217-333-1652
- Views
- 205
- 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.