Competition of Topological and Nematic Phases in the Two-dimensional Electron Gas

Condensed Matter Seminars

Speaker: Gábor Csáthy, Department of Physics and Astronomy and the Birck Nanotechnology Center, Purdue University
Date & Time: December 1, 2016 2:00 - 3:00
Location: Hennings 318
Local Contact: Josh Folk
Intended Audience: Graduate

The two-dimensional electron gas is a prototypical strongly correlated system which, over the years, has contributed to the development of novel concepts in condensed matter physics such as fractional charge, composite fermions, edge states, Pfaffian correlations, non-Abelian statistics, and topological order. The two-dimensional electron gas hosted in GaAs/AlGaAs heterostructures has a particularly rich set of ground states. Well-known examples are the fractional quantum Hall states and various exotic electronic solids.

In this talk I will discuss a recently observed pressure driven phase transition at ν=5/2 from a fractional quantum Hall state to a nematic state. Since the former is a topological phase and the latter a traditional broken symmetry phase, the observed transition is an interesting example of a phase transition from a topologically ordered to a broken symmetry phase.