STRONG SUPPRESSION OF SPIN SPLITTING IN QUANTUM WIRES DUE TO CORRELATIONS INDUCED BY EDGE STATE SCREENING

A modified local-density approximation is developed to treat self-cons istently exchange and correlations in a quantum wire (QW) subjected to a strong perpendicular magnetic field. The influence of many-body int eractions on the spin splitting between the two lowest Landau levels ( LLs) is calculated within the screened Hartree-Fock approximation (SHF A), for filling factor nu = 1, and the strong spatial dependence of th e screening properties of electrons is taken into account. In comparis on with the Hartree-Fock result, the spatial behaviour of the occupied LLs in a QW is strongly modified when correlations are included. Corr elations caused by bulk screening are very weak whereas those caused b y screening at the edges are very strong. The latter strongly suppress the exchange splitting and smoothen the energy dispersion at the edge s. The theory is in reasonable agreement with the observed strong supp ression of the spin splitting pertinent to the nu = 1 quantum Hall eff ect (QHE) state and the destruction of this state in long QWs.