Dresden 2003 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 14: Poster I

HL 14.75: Poster

Montag, 24. März 2003, 17:00–19:30, HSZ/P2

Ab initio Determination of Correlated Wavefunctions for Excited Hole and Electron Capture States in Solids — •Uwe Birkenheuer, Christa Willnauer, and Malte von Arnim — Max-Planck-Institut für Physik komplexer Systeme, Dresden

A new scheme is presented which allows to perform wavefunction-based quantum chemical correlation calculations for solids. It is based on localized Hartree-Fock orbitals (occupied and virtual ones). Exploiting the predominantly local character of electron correlation it is possible to re-cast a wavefunction-based correlation calculation of an infinite system by a series of restricted correlation calculations in finite variational spaces. This incremental scheme has successfully been applied to the ground properties of various non-metallic materials.

Here, we present an extension of this method for hole and electron capture states, leading to the valence and conduction band structures of the solid. It is based on the effective Hamiltonian approach and an embedding formalism which correctly incorporates the environmental effects during the restricted correlation calculations.

The band structure of diamond is presented as obtained by MR-CI(SD) and MR-ACPF calculations with cc-pVDZ and cc-pVTZ basis sets. It is demonstrated that the Hartree-Fock band gap of diamond (≈ 14 eV) is signifcantly reduced by the electron correlation, resulting in values quite close to the experimental data of ≈ 7.5 eV.