Regensburg 1998 – scientific programme

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TT: Tiefe Temperaturen

TT 20: Korrelierte Elektronen (Theorie) I

TT 20.1: Invited Talk

Thursday, March 26, 1998, 14:30–15:00, H 18

Spin Polarizations of Interacting Electrons in a Narrow Quantum Hall System — • T. Chakraborty — Max-Planck Institut für Physik Komplexer System, Nöthnitzer Strasse 38, 01187 Dresden

We discuss the electronic properties of a system of interacting electrons in a narrow channel in the quantum Hall effect regime. We demonstrate that the system undergoes phase transitions when the strength of the interaction or the geometry of the channel is varied. The resulting phase diagram contains odd-denominator quantum Hall states and also a stable ν=1/2 state [1]. The collective mode evaluated at the half-filled case is strikingly similar to that of an odd-denominator quantum Hall state. We analyze the spin polarizations of those stable quantum Hall states as a function of temperature. At ν=1/2 no two-dimensional analog exists, but for the odd-denominator states, the temperature dependence closely resemble the ones in the corresponding two-dimensional systems which received support from recent experiments [3]. We also discuss the nature of the phases with non-zero total momentum or with no energy gap, and the effect of impurities (Gaussian repulsive impurities) on the phase diagram.

[1] T. Chakraborty et al., Phys. Rev. Lett. 78, 4829 (1997)

[2] T. Chakraborty and P. Pietiläinen, Phys. Rev. Lett. 76, 4018 (1996)

[3] I.V. Kukushkin, K. von Klitzing, and K. Eberl, Phys. Rev. B 55, 10607 (1997); S.E. Barrett, et al., Phys. Rev. Lett. 74, 5112 (1995)