Münster 1999 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

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 21.69: Poster

Donnerstag, 25. März 1999, 14:30–18:00, Foy

Quantum Critical Behavior in a Ferromagnetic Kondo Model — •Y. Wang and U. Eckern — Theoretische Physik II, Institut für Physik, Universität Augsburg, D-86135 Augsburg

To study the impurity potential effect on the Kondo problem in a Luttinger liquid, we propose an integrable model of two interacting half-chains coupled ferromagnetically by a single magnetic impurity. It is shown that the scalar potential has a significant effect on the spin dynamics at low temperatures. Generally, there is a competition between the Kondo coupling J and the impurity potential V. When the ferromagnetic Kondo coupling dominates over the impurity potential (V<|SJ|), the Furusaki-Nagaosa many-body singlet can be perfectly realized. However, when the impurity potential dominates over the Kondo coupling (V≥ |SJ|), the fixed point predicted by Furusaki and Nagaosa is unstable and the system must flow to a weak coupling fixed point. We find that the effective moment of the impurity measured from the susceptibility is considerably enlarged by the impurity potential. In addition, some quantum phase transitions driven by the impurity potential are found and the anomal residual entropy is discussed.