Electronic structure of dangling bonds in amorphous silicon studied via a density-matrix functional method

R. G. Hennig, P. A. Fedders, A. E. Carlsson

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12 Scopus citations

Abstract

A structural model of hydrogenated amorphous silicon containing an isolated dangling bond is used to investigate the effects of electron interactions on the electronic level splittings, localization of charge and spin, and fluctuations in charge and spin. These properties are calculated with a recently developed density-matrix correlation-energy functional applied to a generalized Anderson Hamiltonian, consisting of tight-binding oneelectron terms parametrizing hydrogenated amorphous silicon plus a local interaction term. The energy level splittings approach an asymptotic value for large values of the electron-interaction parameter U, and for physically relevant values of U are in the range 0.3-0.5 eV. The electron spin is highly localized on the central orbital of the dangling bond while the charge is spread over a larger region surrounding the dangling bond site. These results are consistent with known experimental data and previous density-functional calculations. The spin fluctuations are quite different from those obtained with unrestricted Hartree-Fock theory.

Original languageEnglish
Article number195213
Pages (from-to)1952131-1952136
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume66
Issue number19
DOIs
StatePublished - Nov 15 2002

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