2012/03/31 by A. Mezio, L. O. Manuel, R. R. P. Singh +1 · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1088/1367-2630/14/12/123033
published as New Journal of Physics. 14 (2012) 123033 · 16 pages, 5 figures
arxiv created 2012/12/20 · arxiv updated 2012/12/21
We study the low temperature properties of the triangular-lattice Heisenberg antiferromagnet with a mean field Schwinger spin-1/2 boson scheme that reproduces quantitatively the zero temperature energy spectrum derived previously using series expansions. By analyzing the spin-spin and the boson density-density dynamical structure factors, we identify the unphysical spin excitations that come from the relaxation of the local constraint on bosons. This allows us to reconstruct a free energy based on the physical excitations only, whose predictions for entropy and uniform susceptibility seem to be reliable within the temperature range 0< T <0.3J, which is difficult to access by other methods. The high values of entropy, also found in high temperature expansions studies, can be attributed to the roton-like narrowed dispersion at finite temperatures.