Manifestation of peak-dip-hump structure in tunneling spectra of cuprates: a study by extended d -wave pairing symmetry

In this study, we examined the relationship between the angular and energy-dependent gap function and the peak-dip-hump structure observed in quasiparticle tunneling spectra within high-temperature superconductor–insulator–normal metal (HTSC-I-N) junctions. We analyzed the tunneling spectra in HTSC-I-N junctions, focusing on the peak-dip-hump structure, using the extended d -wave pairing symmetry and the polaron approach. We investigated two significant aspects of the tunneling spectra observed in experiments, namely, the temperature and doping-dependent evolution of the differential conductance. Furthermore, we estimated the dependence of the pseudogap on hole doping in the cuprate phase diagram by comparing the difference between the binding energies of large polarons and their Coulomb interaction energies. Our calculated results were then compared with experimental data. Importantly, we found a strong quantitative agreement between the theoretical predictions and the experimental observations in the considered cases. Graphic abstract