Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: CE: Metal-Insulator Transition 2

TT 19.8: Hauptvortrag

Mittwoch, 24. März 2010, 11:15–11:45, H18

Spectroscopy on Strongly Correlated Electron Materials — •Liu Hao Tjeng — Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany

One of the most intriguing aspects of transition metal materials is the wide variety of their physical properties. Although conceptually clean and beautiful, theoretical simplifications in terms of, for instance, a single band Hubbard model turn out to be inadequate. It now becomes clear that the interplay between the relevant charge, orbital and spin degrees of freedom of the metal ions involved determines the intricate balance between band formation and electron-correlation effects.

In this talk we would like to illustrate how synchrotron-based electron spectroscopies can contribute to the identification of the key parameters in the electronic structure of transition metal oxides, in particular those showing metal-insulator transitions as a function of temperature or doping. We use a combination of soft-x-ray absorption spectroscopy and photoemission, as well as the newly developed hard-x-ray photoelectron spectroscopy (HAXPES), to address issues related to the inter-site spin-spin and orbital-orbital correlations. Furthermore, we will address how accurate these phenomena can be theoretically described using the LDA+DMFT method and its most recent extensions.

In collaboration with Z. Hu, M. Haverkort, T. Koethe, C.F. Chang, H. Wu, T. Burnus, Y. Chin, N. Hollmann, H. Fujiwara, C. Schußler-Langeheine, H. Roth, M. Benomar, M. Reuther, C. Zobel, T. Lorenz, D. Khomskii, A. Tanaka, E. Pavarini, W. Reichelt, S. Barilo, J. Cezar, N. Brookes, H.H. Hsieh, H.J. Lin, C.T. Chen. Supported by SFB 608.