We present a calculation of the wavevector-dependent subband level splitting from spin-orbit coupling in Si/SiGe quantum wells. We first use the effective-mass approach, where the splittings are parameterized by separating contributions from the Rashba and Dresselhaus terms. We then determine the parameters by fitting tight-binding numerical results obtained using the quantitative nanoelectronic modeling tool, NEMO-3D. We describe the relevant parameters as a function of applied electric field and well width in our numerical simulations. For a silicon membrane, we find the bulk Rashba parameter to be linear in field, α=α1Ez with α1≃2× 10 −5nm−2. The dominant contribution to the spin-orbit splitting is from Dresselhaus-type terms, and the magnitude for a typical flat SiGe/Si/SiGe quantum well can be as high as 1μeV.
@article{arxiv.0908.2417,
title = {Spin-orbit splittings in Si/SiGe quantum wells},
author = {M. Prada and G. Klimeck and R. Joynt},
journal= {arXiv preprint arXiv:0908.2417},
year = {2009}
}