Dynamical effects in crystalline solid state systems: theory of temperature dependent optical response of bulk gaAs and vibrational modification of C(111) 2 x 1 Surface in Comparison to Experiment
Date
2009-08-01
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Abstract
This thesis presents a new theoretical formalism which incorporates dynamical effects in
atomistic electronic structure and related calculations.
This research, fundamental by nature, brings about a deeper understanding of the dynamical
processes in a range of materials. This establishes technologically important correlation
with experimentally measured macroscopic properties and materials characterization. This
method—the first of its kind—is a natural and long overdue extension of customary adiabatically
separated time-independent electronic structure methods. It accounts explicitly for
atomic motion due to thermal and zero-point vibration. The approach developed requires
no direct treatment of time dependence in the quantum mechanical calculations, making
the method widely applicable utilizing currently available electronic structure and ab-initio
molecular dynamics software.
The formalism is extensively applied and demonstrated for the linear optical response
of bulk gallium arsenide and electronic structure of the C(111) 2 x 1 surface. Both cases
are complimented by comparison of key observables to experimental data which may be
used to judge the quality of the results. The results are found to be in good agreement with
experimental data, with most exceptions being readily explainable and well understood.
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Keywords
Dynamical effects, Thermally perturbed band structure and optical response, Di-electric properties, Gallium arsenide, Semiconductor surfaces, Zero-point vibrations, C(111) 2x1 reconstruction