Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 12: Correlated Electrons: Low-dimensional Systems - Models

TT 12.2: Vortrag

Dienstag, 28. März 2006, 09:45–10:00, HSZ 304

Magnetic properties of 2D frustrated spin systems at finite temperatures — •Burkhard Schmidt, Nic Shannon, and Peter Thalmeier — Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden

We present an analysis of the magnetic properties of two-dimensional frustrated spin systems at finite temperatures. Our numerical results are determined using the finite-temperature Lanczos method for small clusters of spins [1].

In particular, the magnetisation of the two-dimensional frustrated J₁-J₂ Heisenberg model on a square lattice will be discussed as a function of temperature, applied magnetic field, and frustration angle φ=tan⁻¹(J₂/J₁). We will cover the full phase diagram of the model with φ=−π…π, with a focus on the two spin-liquid regions at the edges of the collinear antiferromagnetic phase (ordering vector (π,0) or (0,π)) for both ferro- and antiferromagnetic nearest-neighbour coupling J₁.

Experimental realisations of the model discussed are two-dimensional layered Vanadate compounds. A comparison to the available experimental data will be given.

[1] N. Shannon et al., Eur. Phys. J. B 38 (2004) 599