Europhys. Lett.
Volume 63, Number 4, August 2003
Page(s) 569 - 575
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00553-2
Europhys. Lett., 63 (4) , pp. 569-575 (2003)

Spin and charge dynamics of stripes in doped Mott insulators

F. F. Assaad1, 2, V. Rousseau3, F. Hebert4, M. Feldbacher1 and G. G. Batrouni3

1  Institut für Theoretische Physik III, Universität Stuttgart Pfaffenwaldring 58, D-70550 Stuttgart, Germany
2  Max Planck Institute for Solid State Research Heisenbergstr. 1, D-70569 Stuttgart, Germany
3  Institut Non-Linéaire de Nice, Université de Nice-Sophia Antipolis 1361 route des Lucioles, 06560 Valbonne, France
4  Theoretische Physik, Universität des Saarlandes - 66041 Saarbrücken, Germany

(Received 25 November 2002; accepted in final form 10 June 2003)

We study spin and charge dynamics of stripes in doped Mott insulators by considering a two-dimensional Hubbard model with N fermion flavors. For N=2 we recover the normal one-band model while for $N\rightarrow\infty$ a spin density wave mean-field solution. For all band fillings, lattice topologies and N=4n, the model may be solved by means of quantum Monte Carlo methods without encountering the sign problem. At N=4 and in the vicinity of the Mott insulator we find a stripe phase. This phase has a quasiparticle gap but conducts due to long-wavelength low-lying collective charge modes.

71.27.+a - Strongly correlated electron systems; heavy fermions.
71.10.Fd - Lattice fermion models (Hubbard model, etc.).

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