Energy spectrum and low temperature entropy of the spin-1/2 triangular antiferromagnet

MEZIO, ALEJANDRO; SPOSETTI, CINTIA N.; MANUEL, LUIS O.; TRUMPER, ADOLFO E.

San Miguel de Tucumán

Congreso; IV Reunión Nacional de Sólidos; 2011

Laboratorio de Física del Sólido - FCET - UNT

We present results of the dynamical structure factor for the spin-1/2triangular Heisenberg model, recently computed by us, using the meanfield Schwinger boson theory. We find that a reconstructed dispersion,resulting from a non trivial redistribution of the spectral weight, agreesquite well with the spin excitation spectrum found with series expansions.In particular, we recover the strong renormalization with respect to linearspin wave theory along with the appearance of roton-like minima at themidpoints of edges of the hexagonal Brillouin zone. By computing thedensity-density dynamical structure factor, we identify an unphysical weaksignal of the spin excitation spectrum with the relaxation of the local