Features of the competition of the spin and pseudospin subsystems in the model cuprate

We consider the competition of magnetic and charge ordering in model cuprate within the framework of the simplified static 2D spin-pseudospin model. This model is equivalent to the 2D dilute antiferromagnetic (AFM) Ising model with charged impurities. We present the mean-field results for the system under study and make a brief comparison with classicalMonte Carlo (MC) calculations. Numerical simulations show that the cases of strong exchange and strong charge correlation differ qualitatively. For a strong exchange, the AFM phase is unstable with respect to the phase separation (PS) into the pseudospin (charge) and magnetic (spin) subsystems, which behave like immiscible quantum liquids. An analytical expression was obtained for the PS temperature.