Subharmonic energy-gap structure and heating effects in superconducting niobium point contacts

Subharmonic energy-gap structure in superconducting weak links.

Subharmonic shapiro steps and assisted tunneling in superconducting point contacts.

We analyze the current in a superconducting point contact of arbitrary transmission in the presence of a microwave radiation. The interplay between the ac Josephson current and the microwave signal gives rise to Shapiro steps at voltages V = (m/n)h(omega)(r)/2e, where n,m are integer numbers and omega(r) is the radiation frequency. The subharmonic steps (n not equal 1) are a consequence of mult...

Effect of rf on subharmonic gap structure in superconducting junctions

2014 The rf-power dependence of the structure in the current-voltage characteristic located at the voltage V = (2 0394 ± nhv)/me has been measured and found very similar to the familiar microwave-assisted tunneling (m = 1). 2 0394 is the superconducting energy gap, v the applied frequency, m = 1, 2, 3, ... and n = 0, 1, 2, ... That is, the variation with power of all these structures is found c...

Sensing with Superconducting Point Contacts

Superconducting point contacts have been used for measuring magnetic polarizations, identifying magnetic impurities, electronic structures, and even the vibrational modes of small molecules. Due to intrinsically small energy scale in the subgap structures of the supercurrent determined by the size of the superconducting energy gap, superconductors provide ultrahigh sensitivities for high resolu...

Subharmonic gap structure in d-wave superconductors

We present a self-consistent theory of current-voltage characteristics of d-wave/d-wave contacts at arbitrary transparency. In particular, we address the open problem of the observation of subharmonic gap structure ~SGS! in cuprate junctions. Our analysis shows that ~i! the SGS is possible in d-wave superconductors; ~ii! the existence of bound states within the gap results in an even-odd effect...