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In the past 25 years electron spectroscopy has developed steadily to take its place with optical and Raman spectroscopy and with neutron scattering as an established general technique for studying the electronic structure of condensed matter systems. Already the current quality of available data on strongly correlated electron systems calls for theory beyond that of the model Hamiltonian. The best current possibility for such theory is that of dynamic mean field theory (DMFT) combined with band theory using the local density approximation (LDA). I will show examples from electron spectroscopy of various f and d electron systems [1-4]. I will compare to theory results from LDA + DMFT where possible, and indicate opportunities where theory is needed.
[1] J. W. Allen, Solid State Commun. 123, 469 (2002). [2] S.-K. Mo et al, Phys. Rev. Lett., 90 186403 (2003). [3] S.-K. Mo et al, Phys. Rev. Lett., 93 076404 (2004). [4] J. W. Allen, J. Phys. Soc. Japan 74, 34 (2005). * Work supported by U.S. NSF under Grant No. DMR-03-02825. |