Spin-orbit Interaction and Spin Relaxation in a Two-Dimensional Electron Gas

Using time-resolved Faraday rotation, the drift-induced spin-orbit field of a two-dimensional electron gas in an InGaAs quantum well is measured. Including measurements of the electron mobility, the Dresselhaus and Rashba coefficients are determined as a function of temperature between 10 and 80 K. By comparing the relative size of these terms with a measured in-plane anisotropy of the spin-dephasing rate, the D'yakonov-Perel' contribution to spin dephasing is estimated. The measured dephasing rate is significantly larger than this, which can only partially be explained by an inhomogeneous $g$ factor.