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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.118: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Quantum Monte Carlo Study of Dimerized Heisenberg Models — •Sandro Wenzel, Leszek Bogacz, and Wolfhard Janke — Institut für Theoretische Physik, Universität Leipzig, Augustusplatz 10/11, 04109 Leipzig

In this contribution we study two-dimensional anti-ferromagnetic dimerized Heisenberg systems such as the J−J^′ model [1] given by the Hamiltonian

for S=1/2 and generalisations thereof [2]. Here, ⟨ i,j ⟩₁ and ⟨ i,j ⟩₂ denote two different kinds of nearest neighbour bonds that are distributed on the square lattice in a regular fashion.

Such models play an important role in the study of quantum effects in low-dimensional magnetic systems. The focus of our research will be on the ground state phase diagram (T→ 0) and the magnetization properties for h>0. We will present results of our investigations of the model by means of the Stochastic Series Expansion [3] (SSE) Quantum Monte Carlo scheme. Finally, we compare our findings with approximate theoretical results obtained for the J−J^′ model in [1].

[1] S.E. Krüger, J. Richter, J. Schulenberg, D.J.J. Farnell, and R.F. Bishop, Phys. Rev. B 61 (2000) 14607.

[2] M. Matsumoto, C. Yasuda, S. Todo, and H. Takayama, Phys. Rev. B 65 (2001) 014407.

[3] O.F. Syljuasen and A.W. Sandvik, Phys. Rev. E 66 (2002) 046701.