1112.4439 (Rajiv R. P. Singh et al.)

Corrections to Pauling residual entropy and single tetrahedron based
approximations for the pyrochlore lattice Ising antiferromagnet    [PDF]

Rajiv R. P. Singh, J. Oitmaa

We study corrections to single tetrahedron based approximations for the entropy, specific heat and uniform susceptibility of the pyrochlore lattice Ising antiferromagnet, by a Numerical Linked Cluster (NLC) expansion. In a tetrahedron based NLC, the first order gives the Pauling residual entropy of ${1\over 2}\log{3\over 2}\approx 0.20273$. A 16-th order NLC calculation changes the residual entropy to 0.205507 a correction of 1.37 percent over the Pauling value. At high temperatures, the accuracy of the calculations is verified by a high temperature series expansion. We find the corrections to the single tetrahedron approximations to be at most a few percent for all the thermodynamic properties.

View original: http://arxiv.org/abs/1112.4439