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TT: Tiefe Temperaturen

TT 21: Postersitzung III: Hochfrequenzeigenschaften (1-4), Amorphe Systeme (5-9), Borkarbide (10-18), Quantenflüssigkeiten (19-25), Dünne Filme (26-49), Vortexdynamik, Pinning (50-63), M-I-Überg
änge, quantenkritische Ph
änomene (64-89)

TT 21.70: Poster

Thursday, March 25, 1999, 14:30–18:00, Foy

Temperature-dependent dynamic properties of the 2D Kondo insulator — •C. Gröber and R. Eder — Institut fuer Theoretische Physik, Universität Würzburg, Am Hubland 97074, Germany

We present a Quantum Monte Carlo (QMC) study of the temperature dependent dynamics of the two-dimensional Kondo insulator. Working at the so-called symmetrical point allows to perform minus-sign free QMC simulations. Study of the temperature dependence of the single-particle Green’s function and the dynamical spin correlation function as well as of the static charge- and spin-susceptibilities shows surprisingly intricate low temperature physics and gives evidence for two characteristic temperatures, namely the Kondo and the coherence temperature. In particular, the data show that the temperature induced metal-insulator transition at the coherence temperature in two-dimensions is driven by antiferromagnetic (AF) spin-correlations for large interaction values.