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