Valley Splitting in V-Shaped Quantum Wells
Date of this Version5-23-2005
Journal of Applied Physics 97, 113702 (2005).
We especially acknowledge interesting discussions with S. N. Coppersmith; we also thank M. Friesen, R. Joynt, and M. A. Eriksson for useful conversations. Work at JPL and UAH sponsored in major proportion by the U.S. Army Research Office through the ARDA program and directly through ARDA. The work at Purdue was supported by the National Science Foundation, Grant No. EEC-0228390. part of the work described in this publication was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. Funding was provided at JPL under grants from ARDA, ONR, and JPL.
The valley splitting energy difference between the states of the lowest doublet in strained silicon quantum wells with a V-shaped potential is calculated variationally using a two-band tight-binding model. The approximation is valid for a moderately long approximately 5.5 – 13.5 nm quantum well with a V-shaped potential which can be produced by a realistic delta-doping on the order of nd 1012 cm−2. The splitting versus applied ﬁeld steepness of the V-shaped potential curves show interesting behavior: a single minimum and for some doublets, a parity reversal as the ﬁeld is increased. These characteristics are explained through an analysis of the variational wave function and energy functional.