Berlin 2005 – scientific programme

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Low-dimensional Systems: Models

TT 25.8: Talk

Tuesday, March 8, 2005, 11:45–12:00, TU H2053

Spin Gap in a Spiral Staircase Model — •Mikhail Kiselev¹, Dimitry Aristov², and Konstantin Kikoin³ — ¹Insitut for Theoretical Physics and Astrophysics, Würzburg University, 97074 Würzburg, Germany — ²Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany — ³Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel

We investigate the formation of spin gap in one-dimensional models characterized by the groups with hidden symmetries. We introduce a new class of Hamiltonians for description of Spin Staircases - the spin systems intermediate between 2-leg ladders and S=1 spin chains. The spin exchange anisotropy along legs is described by the angle of spiral twist. The properties of a special case of Spin Rotator Chain (SRC) corresponding to a flat 1-leg ladder is considered by means of fermionization approach based on Jordan-Wigner transformation. The influence of dynamical hidden symmetries on the scaling properties of the spin gap is discussed.