CMP Seminar

	Monday, September 23, 2002
	4:10 p.m., Room 1400 Biomedical Physical Sciences Building
	Refreshments served at 3:45 p.m.


"Quantum Hall Liquid Crystals"

Carlos Wexler, University of Missouri-Columbia

Abstract:

Recently, a plethora of new phenomena has emerged in the transitional
regions between different plateaus of the Hall conductance of high Landau
levels (LL).  Near half-filling of the valence LL, extreme anisotropy in
the magnetotransport has been measured below ca. 100 mK.  This anisotropic
behavior has been attributed to the formation of a liquid crystalline
phase with either smectic (positional and orientational) or nematic
(orientational) order.  In this talk I will present a first principles
derivation of the low energy modes of such a state leading to an
equivalent elastic model of this novel phase.  This leads to a
qualitatively correct prediction of the anisotropic-isotropic transition
via the Kosterlitz-Thouless disclination unbinding mechanism.  If time
permits, I will also present an alternative microscopic derivation of a
quantum Hall nematic state.