Schedule Nov 19, 2002
Prominent Metal Phase Quasi-particle Peak and High Temperature Correlation Gap Filling in Photoemission Spectra of (V1-xCrx)2O3 : Comparison to LDA + DMFT Theory
James Allen, University of Michigan
We have discovered in the photoemission spectrum of the metal phase of (V1-xCrx)2O3 a prominent quasi-particle peak at the Fermi energy, of amplitude larger than the rest of the V 3d spectrum by a factor approaching two. This result was achieved by using high photon energy to maximize bulk sensitivity and a small photon spot to minimize the sampling of steps and edges on typical cleaved surfaces. The peak is qualitatively much like that found in new 300K LDA+DMFT(QMC) theory, but shows important differences quantitatively. The paramagnetic insulating phase spectral shape shows large differences even with 300K theory spectra. We have also made high temperature studies of the PI phase using low photon energies in the UM home lab and observe high temperature correlation gap filling, qualitatively as predicted by theory.

Work supported by the U.S. NSF at UM (DMR-9971611), by U.S. DoE at UM (DE-FG-02-90ER45416), by Grant-in-Aid for COE Research (10CE2004) of MEXT, Japan , by JASRI (2000B0335-NS-np), by the Deutsche Forschungsgemeinschaft (DFG) through SFB 484, by the Emmy-Noether program of the DFG, by the Russian Foundation for Basic Research grant RFFI-01-17063, by the Alexander van Humboldt-Foundation and by the Leibniz-Rechenzentrum, München.

** S.-K. Mo1, J.D. Denlinger2, Hyeong-Do Kim3, J.-H. Park4, J.W. Allen1, A. Sekiyama5, A. Yamasaki5, K. Kadono5, S. Suga5, Y. Saitoh6, T. Muro7, P. Metcalf8, G. Keller9, K. Held10, V. Eyert11, V.I. Anisimov12 and D. Vollhardt9

  1. Randall Laboratory, University of Michigan, Ann Arbor, MI 48109 USA
  2. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
  3. Pohang Synchrotron, Pohang 790-784, Korea
  4. Dept. of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
  5. Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan
  6. Dept. of Synchrotron Radiation Research, Japan Atomic Energy Research Institute, Spring-8, Sayo, Hyogo 679-5143, Japan
  7. Japan Synchrotron Radiation Research Institute, Spring-8, Sayo Hyogo 679-5143, Japan
  8. Department of Physics, Purdue University, West Lafayette, IN 47907 USA
  9. Theoretical Physics III, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
  10. Max Planck Institute for Solid State Research, Heisenbergstrasse I, D-70569 Stuttgart, Germany
  11. Theoretical Physics II, University of Augsburg, 86135 Augsburg, Germany
  12. Institute of Metal Physics, Ekaterinburg GSP-170, Russia

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