Direct calculation of the spin stiffness on square, triangular and cubic   lattices using the coupled cluster method
  We present a method for the direct calculation of the spin stiffness by means of the coupled cluster method. For the spin-half Heisenberg antiferromagnet on the square, the triangular and the cubic lattices we calculate the stiffness in high orders of approximation. For the square and the cubic lattices our results are in very good agreement with the best results available in the literature. For the triangular lattice our result is more precise than any other result obtained so far by other approximate method. 
S. E. Kr\"uger, R. Darradi, J. Richter and D. J. J Farnell