Spin-1/2 Heisenberg antiferromagnet on thekagome´ lattice: High-temperature expansion and exact-diagonalization studies

N. Elstner, A. P. Young
1994 Physical Review B (Condensed Matter)  
For the spin-1/2 Heisenberg antiferromagnet on the Kagomé lattice we calculate the high temperature series for the specific heat and the structure factor. A comparison of the series with exact diagonalisation studies shows that the specific heat has further structure at lower temperature in addition to a high temperature peak at T≈ 2/3. At T=0.25 the structure factor agrees quite well with results for the ground state of a finite cluster with 36 sites. At this temperature the structure factor
more » ... structure factor is less than two times its T=∞ value and depends only weakly on the wavevector q, indicating the absence of magnetic order and a correlation length of less than one lattice spacing. The uniform susceptibility has a maximum at T≈ 1/6 and vanishes exponentially for lower temperatures.
doi:10.1103/physrevb.50.6871 pmid:9974644 fatcat:7k752a5625bafbdbo47or7nkwq