Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 51: Electron Theory of Magnetism

MA 51.4: Vortrag

Freitag, 4. April 2014, 10:15–10:30, HSZ 401

The phase diagram of the xxz model on the triangular lattice — •Daniel Sellmann, XUE-FENG ZHANG, and Sebastian Eggert — University of Kaiserslautern, Germany

The Heisenberg model on the triangular lattice was proposed as the first example of a spin-liquid by Anderson in the early 70s. Even though the isotropic Heisenberg model is by now well understood and known not to be a spin-liquid in the modern sense, there are still no quantum many-body simulations which have explored the full phase diagram of the xxz model on the triangular lattice. We now present DMRG calculations on order parameters and entanglement measures in order to establish the quantitative phase diagram as a function of field and Ising anisotropy. The transition to the xy-phase is always first order, but there is a novel tricritical point at the transition to the 1/3-Neel phase. The neel phase is connected to two different supersolid-type phases by second order phase transitions, one of which curiously turn first oder in the Ising limit.