Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique

TT 16.59: Poster

Samstag, 5. März 2005, 11:00–16:30, Poster TU C

Ab-initio Phonons for the layered compound TiOCl — •Leonardo Pisani and Maria-Roser Valenti — Institute for Theoretical Physics, University of Frankfurt, 60054 Frankfurt, Germany

We present first-principles frozen-phonon calculations for the determination of the three Raman-active A_g modes in the spin-1/2 layered TiOCl system within two different well-known approaches: the generalized gradient approximation (GGA) and the so-called LDA+U approximation. We observe that the inclusion of electron correlation in a mean-field level as implemented in the LDA+U leads to a better overall agreement with experimental results. We also discuss the implications of the two approaches on the physics of TiOCl.