Condensed Matter Seminar: Prof. Ilya Esterlis, University of Wisconsin-Madison

The two-dimensional electron gas (2DEG) is one of the simplest models in condensed matter physics to write down, yet has a rich phase diagram that exhibits a variety of interesting correlated phenomena. At high electron density the system behaves essentially as a gas, while at low density the system freezes into the Wigner crystal solid. While these extreme limits are well understood, there is a broad range of intermediate densities where the system behaves as a strongly correlated quantum liquid, and in this regime the behavior is still not fully understood. I will discuss how 2D transitional-metal dichalcogenide (TMD) systems promise to be a fruitful platform for interrogating the behavior of the 2DEG in this most interesting regime and will describe experiments demonstrating the existence of Wigner crystal states in these systems, as well as unexpected intermediate phases between the liquid and solid. I will also present new theoretical results that suggest, in contrast to previous reports, the Wigner crystal phase over a broad range of density is likely to be a metallic charge-density wave state, better understood as a "quantum crystal” with a finite concentration of itinerant ground-state defects.