Energy Density Functional Theory In Doped Semiconductors

The Thomas-Ferni (TF) method and i t s r e f i n e m e n t , theThomas-Fermi -Di r a c (TFD) approach have been w i d e l y employedi n the l i t e r a t u r e to study screening i n both metals and semiiconductors, but only for homogeneous and isotropic modelsolids (i.e. within the Local density approximation). Thefrontier of s t a t i c d i e l e c t r i c screening theory in semiconductorsis here extended further to account for exchange-correlationand inhomogeneity within the framework of the energy densityfunctional formalism. In particular, the reciprocal spaceformulation of Langreth and Mehl is used to give exchangecorrelationa nonlocal description. The resulting nonlocalTFD equation is linearized to obtain a closed analyticalexpression for the spatial dielectric function and the rangeof validity is investigated. It is shown that the spatiald i e l e c t r i c function s t i l l has a simple analytical form butthe constants appearing in it have many body effectsincorporated. The present nonlocal Thomas-Fermi-Di ractheory (TFD-NLDA) is more effective at reducing a t t r a c t i vepotentials than all previous linear or nonlinear screeningtheories based on the TF method.

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