Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Density functional theory and beyond for real materials II
O 55.3: Vortrag
Mittwoch, 24. März 2010, 15:30–15:45, H34
Self-doping Effects at a 45∘ Grain Boundary in YBa2Cu3O7 — •U. Schwingenschlögl1 and C. Schuster2 — 1KAUST, PCSE Division, P.O. Box 55455, Jeddah 21534, Saudi Arabia — 2Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany
The charge redistribution at grain boundaries determines the applicability of high-Tc superconductors in electronic devices because the transport across the grains can be hindered considerably. We investigate the local charge transfer and the modification of the electronic states in the vicinity of the grain-grain interface by ab-initio calculations for a normal-state 45∘ [001] grain boundary in YBa2Cu3O7. Our results explain the suppressed interface transport and the influence of grain boundary doping in a quantitative manner, in accordance with the experimental situation. The charge redistribution is found to be strongly inhomogeneous, which has a substantial effect on transport properties since it gives rise to a self-doping of 0.10±0.02 holes per Cu atom. Reference: Phys. Rev. Lett. 102, 227002 (2009).