Magnons versus free spinons in finite quantum frustrated antiferromagnets

I. J. HAMAD; L. O. MANUEL; A. E. TRUMPER

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 404 p. 2858 - 2860

0921-4526

We have investigated the validity of doping with a vacancy the J1–J3 frustrated Heisenberg model on a finite square lattice as a way to test the existence of fractional spin excitations. Using a generalized t–J1–J3 model we have computed the vacancy spectral functions in the self-consistent Born approximation. We have found that by including spiral fluctuations in the magnetic ground state, the spectral functions on finite systems agree very well with the unbiased exact ones. In contrast to the recent proposal that the quasiparticle weight reduction could be a signal of a spinon free excitation in finite systems, we have found strong evidence that such a reduction is due to the existence of spiral fluctuations.