Physical Review B 78, 195310 (2008)
Diffusion Monte Carlo study of a valley degenerate electron gas and application to quantum dots
G. J. Conduit1 and P. D. Haynes2
1Theory of Condensed Matter, Department of Physics,
University of Cambridge, Cavendish Laboratory,
19 J. J. Thomson Avenue, Cambridge CB3 0HE,
UK
2Departments of Physics and Materials,
Imperial College London, Exhibition Road, London SW7 2AZ, UK
A many-flavor electron gas (MFEG) in a semiconductor with a valley
degeneracy ranging between 6 and 24 was analyzed using diffusion Monte
Carlo (DMC) calculations. The DMC results compare well with an
analytic expression derived by one of us [Phys. Rev. B 78, 035111
(2008)] for the total energy to within ±1 % over an order of
magnitude range of density, which increases with valley
degeneracy. For Bi2Te3 (six-fold valley
degeneracy) the applicable charge carrier densities are between
7×1019 cm-3 and 2×1020
cm-3. DMC calculations distinguished between an exact and a
useful approximate expression for the 24-fold degenerate MFEG
polarizability for wave numbers 2pF < q <
7pF. The analytical result for the MFEG is
generalized to inhomogeneous systems by means of a gradient
correction, the validity range of this approach is obtained. Employed
within a density-functional theory calculation this approximation
compares well with DMC results for a quantum dot.
Last updated: 5 August 2010