Low-temperature behavior of two-dimensional quantum antiferromagnets

Abstract

Recent neutron-scattering data for the spin-correlation length in ${\mathrm{La}}_{2}$${\mathrm{CuO}}_{4}$ can be fitted quantitatively with an analysis of the quantum mechanical nonlinear \ensuremath{\sigma} model in two space dimensions. The coupling constant must be chosen in the range where an isolated ${\mathrm{CuO}}_{2}$ layer has antiferromagnetic order at T=0. The parameters are consistent with the spin-wave theory for the nearest-neighbor spin-(1/2 Heisenberg antiferromagnet on a square lattice.