Schedule Nov 18, 2002
Correlation effects in the compressed rare earth metals
Andrew Mc Mahan, LLNL
Three of the rare earth metals (Ce, Pr, Gd) exhibit pressure-induced phase transitions characterized by unusually large volume changes (5-15%), which are believed to be driven by 4f-electron correlation effects. After reviewing systematics of the trivalent rare earth data, and insights from simple one-electron concepts, this talk will turn to the solution of all-valence-orbital effective Hamiltonians generated from local density theory [1], in order to try to understand these phenomena. Hartree-Fock solutions will be contrasted to those of Dynamical Mean-Field Theory in order to illuminate the role played by correlations, and to provide some insight into modified local-density techniques (orbital polarization, self-interaction correction, LDA+U) which like Hartree Fock exhibit some static mean-field character.

Our most comprehensive calculations have been carried out for Ce [2,3], however, some limited results will also be presented for Pr and Nd.

Work by AKM was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. KH acknowledges support by the Alexander von Humboldt foundation, and RTS from NSF-DMR-9985978.

  1. A. K. McMahan, C. Huscroft, R. T. Scalettar, and E. L. Pollock, J. Comput.-Aided Mater. Design 5, 131 (1998).
  2. K. Held, A. K. McMahan, and R. T. Scalettar Phys. Rev. Lett. 87, 276404 (2001)
  3. .
  4. A. K. McMahan, K. Held, and R. T. Scalettar, cond-mat/0208443.

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