Georg-August-Universität Göttingen

Institute of Theoretical Physics

Condensed Matter / A. Honecker / J₁-J₂ Heisenberg chain

Thermodynamics of the J₁-J₂ spin-1/2 Heisenberg chain

This web page provides supplementary material for the paper

1. F. Heidrich-Meisner, A. Honecker, T. Vekua, Frustrated ferromagnetic spin-1/2 chain in a magnetic field: The phase diagram and thermodynamic properties, Phys. Rev. B74 (2006) 020403(R)

and should be considered an integral part thereof. Please consult that paper for definitions and further explanations. We would appreciate if publications making use of information provided on this web page cite the paper [1].

Data files

The following compressed text files tabulate results for several thermodynamic properties of the J₁-J₂ spin-1/2 Heisenberg chain with J₂>0 and h=0 for different values of J₁/J₂ and temperatures 0<T<=5 J₂:

• ring with N=16 sites (approx. 640 KByte in gzip compressed form)
• ring with N=20 sites (approx. 540 KByte in gzip compressed form)

These results are derived from the eigenvalues obtained by full diagonalizations with fixed J₁/J₂ for the given system size N. Changing the temperature grid is straightforward, as is inclusion of an external magnetic field h. However, we think that the files are already big enough with a scan of two parameters and therefore do not include a magnetic field here, but it can easily be added on request. If you need data evaluated at other temperatures or fields, please contact , quoting the parameters (J₁/J₂, T/J₂, h/J₂) which you need.

You will probably use the N=20 data and compare with N=16 to assess finite-size effects, i.e., the influence of the number of spins N being finite.

Figures

To give you a quick overview, we provide below some color-coded plots based on the N=20 data. White regions correspond to large absolute values which have been omitted in order not to blur the rest of the figure. You can download a PDF version of each plot by clicking on it. Curves for J₁=-3 J₂ can be found in our paper [1].

Magnetic susceptibility:

Specific heat:

Specific heat divided by temperature:

Entropy:

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Original version: May 8, 2006, last updated: November 27, 2006; -- don't send me spam!