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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.4: Poster

Donnerstag, 17. März 2011, 10:00–13:00, P1

Kondo physics with variational matrix-product states — •Andrej Schwabe and Michael Potthoff — I. Institut Theoretische Physik, Universität Hamburg, Hamburg, Deutschland

The screening of an impurity spin by conduction band electrons, known as the Kondo effect, is a typical many-particle phenomenon which still raises basic questions. We apply our variational matrix-product states code (VMPS [1,2]) which is based on the implementation of the corrected one-site algorithm [3] and exploits U(1) symmetries. We present calculations for an impurity coupled locally to a finite, but long uncorrelated nano chain as well as calculations for an inhomogeneous two-leg Hubbard-type model with site and leg dependent Hubbard-U.
Our study focuses on the spin correlation functions, which show the emergence of the Kondo screening cloud, and comprises the investigation of its dependence on the position of the impurity, the Kondo coupling, and the length of the chain. The results are compared to previous studies [4,5]. We discuss the interference of the Kondo clouds of several impurities coupled to the chain, and the competition with the magnetic exchange coupling between the impurities (RKKY).
[1] U. Schollwoeck, arXiv:1008.3477v1 (2010)
[2] F. Verstraete et al., Advances in Phys. 57, 143 (2008)
[3] S. R. White, Phys. Rev. B 72, 180403 (2005)
[4] T. Hand et al., Phys. Rev. Lett. 97, 136604 (2006)
[5] A. Holzner et al., Phys. Rev. B 80, 205114 (2009)