Regensburg 1998 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 10: Postersitzung I: Ladungseffekte in Einelektronensystemen (1-6), Niedrigdimensionale Systeme (7-17), Transporteigenschaften und Pinning in HTSL (18-30), Symmetrie des Ordnungsparameters in HTSL (31-36), Korrelierte Elektronen: Theorie (37-79)

TT 10.47: Poster

Dienstag, 24. März 1998, 09:30–13:00, A

Unrestricted Gutzwiller approximation for the two-dimensional Hubbard model — •G. Seibold — Lehrstuhl Theoretische Physik, BTU Cottbus, Postfach 101344, 03013 Cottbus

The Kotliar-Ruckenstein slave-boson scheme [1] is used to allow for an unrestricted variation of the bosonic and fermionic fields on the saddle-point level. Various inhomogeneous solutions, such as spin polarons and domain walls, are discussed within the two-dimensional Hubbard model and compared with results of unrestricted Hartree-Fock (HF) calculations. It turns out that the range of stability for striped phases is considerably enhanced as compared to the HF approximation. Inclusion of a long-range potential leads to the formation of half-filled domain walls which are observed in La_1.6−xNd_0.4Sr_xCuO₄ [2].

[1] G. Kotliar, A. E. Ruckenstein, Phys. Rev. Lett. 57, 1362 (1986)

[2] J. M. Tranquada, B. J. Sternlieb, J. D. Axe, Y. Nakamura, S. Uchida, Nature 375, 561 (1995)