Two‐Dimensional Quantum Antifferomagnet in a Strong Magnetic Field. The Case of Spin 1/2

摘要

AbstractThe problem of the two‐dimensional quantum antiferromagnet of spin 1/2 on a square lattice in a strong transverse magnetic field close to saturation is studied in terms of the equivalent Bose gas problem. The existence of a soft sound‐like mode and of a phase transition from the state with specific canted magnetic structure to the disordered ferromagnetic state is demonstrated. The expressions for thermodynamical and magnetic characteristics are deri