Charge-density-wave origin of the dip-hump structure in tunnel spectra of the BSCCO superconductor
Abstract
Differential conductance $G$ as the function of the bias voltage $V$ across the tunnel junction between a normal metal and an inhomogeneous superconductor with charge density waves (CDW's) has been calculated by spatial averaging over random domains with varying superconducting- and normal-state properties. For these materials, irregularly distorted CDW patterns with spatially scattered values of various parameters were earlier shown to manifest themselves in a great body of experimental data. The results of the calculations were applied to explain the well-known dip-hump structure in the $G(V)$ dependence for ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}\mathrm{Ca}{\mathrm{Cu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ and other high-${T}_{c}$ cuprates.