A microscopic theoretical study of external magnetic field effect on superconductivity and density of states (DOS) in rare earth nickel borocarbide superconductors ( RNi 2 B 2 C ) is reported here. A Hamiltonian model is used to describe the system to which a BCS-type Cooper pairing mechanism is added. The expression for SC order parameter (z) is calculated by the Green's function technique of D. N. Zubarev. The variation of superconducting gap with temperature is investigated at different external magnetic fields. The phase diagram between temperature (θ) and critical magnetic field (bc) agrees with experimental observations. The gap edges in the DOS appear at ±2z in the absence of external magnetic field. On the application of external magnetic field in the DOS, the gap edges appear at ±(z - b) which resembles the tunneling conductance of STM experiment.
Tunneling conductance and local density of states in time-reversal symmetry breaking superconductors under the influence of an external magnetic field
