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TT: Fachverband Tiefe Temperaturen

TT 42: Superconductivity: Fabrication, Properties, Electronic Structure

TT 42.7: Talk

Thursday, March 29, 2012, 16:45–17:00, H 3005

Density functional theory study of alkali doped picene — •Milan Tomić, Hunpyo Lee, Roser Valentí, and Harald Jeschke — Institut für Theoretische Physik, Goethe-Universität, Frankfurt am Main, Germany

We have employed density functional theory methods to determine the equilibrium structures of A_xpicene where A = Na, K, Rb, Cs and x = 1, 2, 3. We have also considered x=4 case in the light of possibility of mixed phase existence. We have found that alkali doping with one, two and three alkali ions per picene molecule leads to subsequent filling of the LUMO and LUMO+1derived bands of picne, leading to quarter, half and three quarter filled systems. We have analysed the electronic structures using tight binding methods to derive the kinetic energy part of the underlying Hubbard Hamiltonian. As the interaction strength U on the picene molecules is expected to be large compared to the bandwidth, we have also employed manybody methods on the resulting Hamiltonian. We have also compared our results to photoemission experiments.