Modeling of Tunneling Spectroscopy in HTSC
  The tunneling density of states of HTSC is calculated taking into account tight binding band structure, group velocity, and tunneling directionality for s-wave and d-wave gap symmetry. The characteristic density of states has quasiparticle peaks' asymmetry, flat s-wave and cusplike d-wave case subgap behavior, and asymmetric background. We consider that the underlying asymmetry of the conductance peaks is primarily due to the features of quasiparticle energy spectrum, and the d-wave symmetry enhances the degree of the peaks' asymmetry. Increasing of the lifetime broadening factor changes the degree of tunneling conductance peaks' asymmetry, and leads to the confluence of the quasiparticle and van Hove singularity peaks. 
Yu. M. Shukrinov, A. Namiranian, A. Najafi