Effect of an in-plane magnetic field on magnetic phase transitions in ν = 2 bilayer quantum Hall systems

By using the effective bosonic spin theory, which was recently proposed by Demler and Das Sarma [Phys. Rev. Lett. 82, 3895 (1999)], we analyze the effect of an external in-plane magnetic field on the magnetic phase transitions of the bilayer quantum Hall system at filling factor ν = 2. It is found that the quantum phase diagram is modified by the in-plane magnetic field. Therefore, quantum phase transitions can be induced simply by tilting the magnetic field. The general behavior of the critical tilted angle for different layer separations and interlayer tunneling amplitudes is shown. We find that the critical tilted angles being calculated agree very well with the reported values. Moreover, a universal critical exponent for the transition from the canted antiferromagnetic phase to the ferromagnetic phase is found to be equal to 1/2 within the present effective theory.