Diffusion Monte Carlo study of a valley-degenerate electron gas and application to quantum dots
نویسندگان
چکیده
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 to 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 sixfold 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 to DMC results for a quantum dot.
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