Spin-orbit splittings in Si/SiGe quantum wells

Abstract

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, $\alpha ={\alpha }^1{E}_z$ with ${\alpha }^1\simeq 2\times$ 10 ${}^{-5}$nm${}^{-2}$. 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 1$\mu$eV.

9 pages, 9 figures

References in corpus (1)

• Electron spin coherence in Si/SiGe quantum wells