Many-body interactions in a quantum wire in the integer quantum Hall regime: Suppression of the exchange-enhancedgfactor

Abstract

The collapse of Hall gaps in the integer quantum Hall liquid in a quantum wire is investigated. Motivated by recent experiment [Pallecchi et al. PRB 65, 125303 (2002)] previous approaches are extended to treat confinement effects and the exchanged enhanced g factor in quantum wires. Two scenarios for the collapse of the ν = 1 state are discussed. In the first one the ν = 1 state becomes unstable at B (1) cr , due to the exchange interaction and correlation effects, coming from the edge-states screening. In the second scenario, a transition to the ν = 2 state occurs at B (2) cr , with a smaller effective channel width, caused by the redistribution of the charge density. This effect turns the Hartree interaction essential in calculating the total energy and changes B (2) cr drastically. In both scenarios, the exchange enhanced g-factor is suppressed for magnetic fields lower than Bcr. Phase diagrams for the Hall gap collapse are determined. The critical fields, activation energy, and optical g-factor obtained are compared with experiments. Within the accuracy of the available data, the first scenario is most probable to be realized.

Magnetoconductance of interacting electrons in quantum wires: Spin density functional theory study

“…9 The effect of the many-body interactions on the spin splitting in quantum wires in the IQH regime has been a subject of numerous studies. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] These studies have focused on various aspects of 2DEG in confined geometries including the structure of compressible/incompressible strips, suppression or enhancement of the g factor, subband spin splitting, spatial spin separation, and others. We, however, have not been able to find in the literature any systematic quantitative treatment of the magnetoconductance of the structures at hand.…”

“…This is due to the exchange and correlations effects leading to the strong enhancement of the electron g factor above its bulk value 9 . The effect of the many-body interactions on the spin splitting in quantum wires in the IQH regime has been a subject of numerous studies 10,11,12,13,14,15,16,17,18,19,20,21,22,23 . These studies have focused on various aspects of 2DEG in confined geometries including the structure of compressible/incompressible strips, suppression or enhancement of the g factor, subband spin splitting, spatial spin sepa-ration and other.…”

Quantum wires in magnetic field: a comparative study of the Hartree–Fock and the spin density functional approaches

“…A powerful tool to study electron-electron interaction and spin effects in quantum wires is the mean-field approach such as the Hartree-Fock (HF) and the spin density functional theory (DFT) [1]. A number of studies based on these approaches addressing various aspects of interacting electrons in the IQH regime in quantum wires have been reported recently [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. However, in some cases different studies produce different results and findings reported in some studies are not recovered in others.…”