Collapse of Spin-Splitting in the Quantum Hall Effect

M. M. Fogler; B. I. Shklovskii

doi:10.1103/PhysRevB.52.17366

paper

Collapse of Spin-Splitting in the Quantum Hall Effect

arXiv:cond-mat/9506084 · doi:10.1103/PhysRevB.52.17366

Abstract

It is known experimentally that at not very large filling factors $ν$ the quantum Hall conductivity peaks corresponding to the same Landau level number $N$ and two different spin orientations are well separated. These peaks occur at half-integer filling factors $ν = 2 N + 1/2$ and $ν = 2 N + 3/2$ so that the distance between them $δ ν$ is unity. As $ν$ increases $δ ν$ shrinks. Near certain $N = N_{c}$ two peaks abruptly merge into a single peak at $ν = 2 N + 1$ . We argue that this collapse of the spin-splitting at low magnetic fields is attributed to the disorder-induced destruction of the exchange enhancement of the electron $g$ -factor. We use the mean-field approach to show that in the limit of zero Zeeman energy $δ ν$ experiences a second-order phase transition as a function of the magnetic field. We give explicit expressions for $N_{c}$ in terms of a sample's parameters. For example, we predict that for high-mobility heterostructures $N_{c} = 0.9 d n^{5/6} n_{i}^{- 1/3},$ where $d$ is the spacer width, $n$ is the density of the two-dimensional electron gas, and $n_{i}$ is the two-dimensional density of randomly situated remote donors.

14 pages, compressed Postscript file

Collapse of Spin-Splitting in the Quantum Hall Effect

Abstract

References in corpus (5)

Cited by in corpus (54)