# Berlin 2005 – wissenschaftliches Programm

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# HL: Halbleiterphysik

## HL 58: Poster IIb

### HL 58.1: Poster

### Dienstag, 8. März 2005, 16:30–19:00, Poster TU F

**Two-particle correlations in crystalline systems** — •K. Morawetz^{1,2}, E. P. Nakhmedov^{3}, B. Schmidt^{1}, M. Schreiber^{1}, and C. Radehaus^{3} — ^{1}Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany — ^{2}Max-Planck-Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany — ^{3}Opto- and solid state electronics, Chemnitz University of Technology, 09107 Chemnitz, Germany

Correlations of two vacancies or defects in crystalline dielectrics are studied by means of a DFT based ab initio method. The dependence of the interaction energy on the defect separation is computed to study the leakage current through a gate dielectric of MOSFET devices. Simulation of the critical radius of the two-particle correlation allows us to suggest a percolation path formation in the dielectrics. As a toy model, the correlated two-particle problem is solved analytically in the presence of a finite cavity. The method is demonstrated here in terms of exactly solvable models for both the cavity as well as the two-particle correlation where the two-particle potential is chosen in separable form. The two-particle phase shift is calculated and compared to the single-particle one. We find a Fano resonance behavior due to the interference of single- and two-particle channels. The two-particle bound state behavior is discussed and the influence of the cavity on the binding properties is calculated.

[1] K. Morawetz, M. Schreiber, B. Schmidt, A. Ficker, P. Lipavský, Phys. Rev. B submitted, cond-mat/0409325

[2] E. P. Nakhmedov, M. Trentzsch, C. Schubert, I. Kabadshow, E. Nadimi, K. Wieczorek, and C. Radehaus, in preparation, 2004