Charge-density-wave origin of the dip-hump structure in tunnel spectra of the BSCCO superconductor

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 Bi₂Sr₂CaCu₂O_8+δ and other high-T_c cuprates.