Density of state and effect of external magnetic field on co-existence state of SC and AFM in high-Tc cuprates

A mean field Hamiltonian model is taken for our system to study density of states and the effect of external magnetic field on superconductivity (SC) and antiferromagnetism (AFM) at the co-existence stage in high-Tc cuprates. The order parameters corresponding to SC and AFM long range orders are determined. The variation of dimensionless superconducting gap (z) and AFM gap (h̃) with temperature are investigated at different magnetic fields. The gap parameters are found to be strongly coupled to each other through their coupling constants. The interplay displays a BCS type of two gaps in the quasi-particle density of states which resemble the tunneling conductance of the STM experiment. The two gap edges in the density of states(DOS) appear at ±(h̃2+z) and ±(h̃2−z). The effect of external magnetic field on DOS is also studied.