arXiv subjects

Ulrich Quaade

Publications and source records attributed to Ulrich Quaade.

2 recordsLinked to original sources

arXiv1997

Electric field effects in STM imaging

We present a high voltage extension of the Tersoff-Hamann theory of STM images, which includes the effect of the electric field between the tip and the sample. The theoretical model is based on first principles electronic structure calculations and has no adjustable parameters. We use the method to calculate theoretical STM images of the monohydrate Si(100)-H(2$\times$1) surface with missing hydrogen defects at $- 2$~V and find an enhanced corrugation due to the electric field, in good agreement with experimental images.

cond-mat.mtrl-sci↗

arXiv1995

BRST quantization of gauge theories like SL(2,R) on inner product spaces

Some general formulas are derived for the solutions of a BRST quantization on inner product spaces of finite dimensional bosonic gauge theories invariant under arbitrary Lie groups. A detailed analysis is then performed of SL(2,R) invariant models and some possible geometries of the Lagrange multipliers are derived together with explicit results for a class of SL(2,R) models. Gauge models invariant under a nonunimodular gauge group are also studied in some detail.

hep-th↗