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 , the Thomas-Fermi -Di r a c (TFD) approach have been w i d e l y employed i n the l i t e r a t u r e to study screening i n both metals and semii conductors, but only for homogeneous and isotropic model solids (i.e. within the Local density approximation). The frontier of s t a t i c d i e l e c t r i c screening theory in semiconductors is here extended further to account for exchange-correlation and inhomogeneity within the framework of the energy density functional formalism. In particular, the reciprocal space formulation of Langreth and Mehl is used to give exchangecorrelation a nonlocal description. The resulting nonlocal TFD equation is linearized to obtain a closed analytical expression for the spatial dielectric function and the range of validity is investigated. It is shown that the spatial d i e l e c t r i c function s t i l l has a simple analytical form but the constants appearing in it have many body effects incorporated. The present nonlocal Thomas-Fermi-Di rac theory (TFD-NLDA) is more effective at reducing a t t r a c t i ve potentials than all previous linear or nonlinear screening theories based on the TF method.

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