THEORY OF COEXISTING TRANSVERSE-SPIN FREEZING AND LONG-RANGED ANTIFERROMAGNETIC ORDER IN LIGHTLY DOPED LA2-XSRXCUO4

We provide an explanation of the spin-freezing transition recently obs erved by Chou et al. [Phys. Rev. Lett. 71, 2323 (1993)] in La2-xSrxCuO 4 for x less than or similar to 0.02. We propose that topological exci tations of the two-dimensional Heisenberg quantum antiferromagnet havi ng noncoplanar transverse components have a pair-interaction energy th at qualitatively and quantitatively agrees with the observed values of spin-freezing temperature as a function of doping.