Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 34: Poster

DY 34.109: Poster

Montag, 7. März 2005, 15:30–18:00, Poster TU D

Quantum Phase Transitions in Inhomogeneous Spin Chains — •Rainer Bischof, Sandro Wenzel, Peter Crompton und Wolfhard Janke — Institute of Theoretical Physics, University of Leipzig, Augustusplatz 10/11, 04109 Leipzig, Germany

We identify the exponents associated with a second order quantum critical point in mixed-periodic spin chains of S = 1/2, 1, 3/2, via quantum Monte Carlo simulations. According to Haldane’s conjecture gaps can occur above the ground state of metallic compounds at low-temperatures, but only for integer spin systems. Our investigation focuses on the experimentally relevant effect of doping quasi-1d metallic compounds with ions of higher spin. We show that, via doping, the original NLSM analysis can be extended to a broader range of systems and newly identify ’spin-glass’ behaviour for half-integer inhomogeneous systems at low-temperatures.