THE CHANGE OF THE HOLE-DISPERSION DUE TO SPIN-CORRELATIONS IN 2D QUANTUM ANTIFERROMAGNETS

The single hole propagation in the antiferromagnetic state of a spin-l iquid type is studied in the t-J model. A ''string'' basis of minimal size is chosen for a hole wave function. The dispersion curves are cal culated for different values of the magnetic correlation length xi. Th e decrease of xi is simulated by a finite temperature within the modif ied spin-wave theory. It is shown that at low temperatures the minimum of the hole band is located at k = (pi/2, pi/2) and the decrease of x i leads to a nearly ''free'' hole propagation with the hand minimum at k = (pi, pi).