Spin-orbit excitations of quantum wells

¹ Dipartimento di Fisica “G. Galilei”, Università di Padova - Via Marzolo 8, Padova, Italy, EU
² Dept. ECM, Facultat de Física, and IN 2 UB - Universitat de Barcelona - Diagonal 647, 08028 Barcelona, Spain, EU
³ Dipartimento di Fisica, University of Trento - via Sommarive 14, I-38050, Povo, Trento, Italy, EU
⁴ INFN, Gruppo Collegato di Trento - Trento, Italy, EU

Received: 19 October 2010
Accepted: 18 March 2011

Abstract

Spin-orbit effects on the photoabsorption of a quantum well are discussed by means of a sum rules approach. We show that while the strength of the excitation is zero when the spin-orbit coupling is neglected, the inclusion of the spin-orbit interaction gives rise to a nonzero strength and mean excitation energy in the far-infrared region. A simple expression for these quantities up to the second order in the Rashba interaction is derived. Modifications of the results due to the Dresselhaus spin-orbit term are discussed. The effect of two-body Coulomb interaction is then studied by means of a Quantum Monte Carlo calculation, showing that electron-electron correlations induce only a small deviation from the independent particle model result.