Elementary electronic excitation from a two-dimensional hole gas in the presence ofspin–orbit interaction

Abstract

We present a theoretical study of the elementary electronic excitation associatedwith plasmon modes in a two-dimensional hole gas (2DHG) in the presence ofspin–orbit (SO) interaction induced by the Rashba effect. The calculation is carriedout using a standard random-phase-approximation approach. It is found that,in such a spintronic system, plasmon excitation can be achieved via intra- andinter-SO electronic transitions around the Fermi level. As a result, the intra- andinter-SO plasmon modes can be observed. More importantly, the plasmon modesinduced by inter-SO transition are optic-like and these modes can be directlyapplied to identify the Rashba spin splitting in 2DHG systems through opticalmeasurements. The interesting features of the plasmon excitation in a spin-split 2DHG areanalysed and discussed in detail. Moreover, the results obtained for a 2DHG arecompared with those obtained for a spin-splitting 2DEG reported very recently.