Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 25: Correlated Electrons - Poster Session
TT 25.25: Poster
Mittwoch, 29. März 2006, 14:30–18:30, P1
Thermodynamics of two-dimensional spatially anisotropic Heisenberg model — •Tatiana Antsygina, Marina Poltavskaya, Konstantin Chishko, and Igor Poltavsky — B. Verkin Institute for Low Temperature Physics and Engineering, Kharkov, Ukraine
Using the formalism of two-time Green’s functions and the decoupling procedure by Kondo and Yamaji we have investigated thermodynamic and magnetic properties of the 1/2-spin Heisenberg antiferromagnet on a spatially anisotropic triangular lattice with nearest neighbor exchange constant J1 along one direction and J2 along other two directions. The thermodynamic functions are expressed in terms of correlation functions which obey the self-consistent system of equation. At arbitrary temperatures the system can be solved only numerically, and temperature dependences of the energy, heat capacity and magnetic susceptibility at different relations between J1 and J2 can be calculated in the wide temperature range. We have analyzed the case ν=J1/J2≪ 1 and found that with the increase of ν the height of the peak on the heat capacity decreases and the peak position shifts to lower temperatures. It is shown that the temperature dependence of the magnetic susceptibility is in excellent agreement with the high temperature series expansions [1]. Possible applications of the theoretical results for the interpretation of physical properties of real low-dimensional magnets are discussed.
0.2cm 1. W. Zheng, R.R.P. Singh, R.H. McKenzie, R. Coldea, cond-mat/0410381.