Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 8: Superconductivity - Poster Session
TT 8.16: Poster
Montag, 26. März 2007, 14:00–17:45, Poster A
Superconductivity in a semiconductor - interband interaction — •Susanne Killiches1 and Khandker Quader2 — 1Institut fuer Physik, Universitaet Rostock — 2Department of Physics, Kent State University, OH USA
Recent experiments [Steiner,Kapitulnik, Physica C, Volume 422, Issue 1-2 p.16-26, 05/2005] have demonstrated that superconductivity can grow out of a non-metallic insulating phase. To explain that phenomena we study a simplified two band model. The idea for explanation is to introduce an attraction in the valence and conduction band of either intra- or inter band nature. The transition to a superconducting phase should occur if the gain in pairing energy by forming an electron-electron pair is greater than its cost [Jrome, Rice, Kohn, Phys. Rev. 158, 462475, 1967]. Using the Matsubara Greens function method, a gap equation for a semiconductor model in 2D is derived, allowing only for inter-band interaction [Nozieres, Pistolesi, European Physical Journal B, Volume 10, #4, 08/1999]. The characteristic gap equation is solved for zero and finite temperature numerically and the behaviour of the transition temperature depending on the excitation gap and order parameter is shown. We find superconductivity, if the coupling exceeds a certain threshold and obtain a successful model to describe the superconductor-insulator transition.