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TT: Tiefe Temperaturen
TT 15: Postersitzung II: Elektronische Eigenschaften (1-12), Josephson-Kontakte (13-27), Heavy Fermions (28-40), Theorie HTSL (41-48), M-I-Überg
änge, Korrelierte Systeme (49-79)
TT 15.66: Poster
Wednesday, March 24, 1999, 14:30–18:00, Foy
Influence of Hybridization on the Properties of the Falicov-Kimball Model — •Gerd Czycholl — Universität Bremen, Institut für Theoretische Physik, D-28334 Bremen
Without a hybridization between the localized f- and the conduction (c-) electron states the spinless Falicov-Kimball model (FKM) is exactly solvable in the limit of high spatial dimension, d → ∞, as first shown by Brandt and Mielsch. Here I show that at least for sufficiently small c-f-interaction this exact inhomogeneous ground state is also obtained in Hartree-Fock approximation. With hybridization the model is no longer exactly solvable, but the approximation yields that the inhomogeneous charge-density wave (CDW) ground state remains stable also for finite hybridization V smaller than a critical hybridization Vc, above which no inhomogeneous CDW solution but only a homogeneous solution is obtained. The spinless FKM does not allow for a ”ferroelectric” ground state with a spontaneous polarization, i.e. there is no nonvanishing <c†f>-expactation value in the limit of vanishing hybridization.