Subbands and correlation effects on plasmon-excitations in quasi-one-dimensional quantum-well wires

Abstract

The plasmon excitations in quasi-one-dimensional quantum-well wires (QWW) are calculated by using the self-consistent-field approximation theory proposed by Singwi, Tosi, Land and Sjölander (STLS). A multisubband model is used in order to investigate the inter- and intra-subband excitations. We present results for the effective potential, structure factor, pair-correlation function and the plasmon dispersion as a function of the wire thickness and the electronic density. The random-phase approximation (RPA) results are also presented for comparison and a sizable deviation from STLS is found. We show that exchange and correlation effects are quite important for a quasi one-dimensional electron gas and when multiple subbands are populated an additional plasmon like intersubband modes exists.