Ground State of a Mobile Vacancy in a Quantum Antiferromagnet: Small Cluster Study.
01 January 1990
The ground state of a mobile vacancy in a square lattice spin- 1/2 Heisenberg antiferromagnet described by the t-J Hamiltonian is investigated numerically for 18 site cluster. The ground state has spin on half and the bottom of the vacancy band is at momentum k=(+- phi/2, +- phi/2), for t/J4, which is consistent with the spin wave perturbation theory. The structure of the spin configuration in the vicinity of the vacancy is examined using a number of correlation functions. The latter reveal the existence of a dipolar distortion of the staggered magnetization as suggested by the semiclassical theory.