Capacitance of Atomic Junctions

Small-capacitance Josephson Junctions: One-dimensional Arrays and Single Junctions

Small-capacitance superconducting tunnel junctions provide an ideal system for studying the interplay between the Josephson phase and the charge on the junction electrode, which are quantum mechanically conjugate to each other. This interplay can be probed through the superconductor-insulator (SI) transition [1], which is a quantum phase transition occurring at T = 0. The SI transition has been...

Interfacial capacitance effects in magnetic tunneling junctions

We have fabricated magnetic tunneling junctions by oxidizing a wedge-shaped aluminum layer to produce junctions with ideal oxidized as well as under and over oxidized junctions on a single wafer. By investigating the capacitance spectra, we are able to study the effects due to interface charge accumulation. The electron–electron interaction among accumulated interface charges leads to a voltage...

Transverse Averaging Technique for Depletion Capacitance of Nonuniform PN-Junctions

This article evolves an analytical theory of nonuniform PN-junctions by employing the transverse averaging technique (TAT) to reduce the three-dimensional semiconductor equations to the quasione-dimensional (quasi-1D) form involving all physical quantities as averaged over the longitudinallyvarying cross section S(z). Solution of the quasi-1D Poisson’s equation shows that, besides the usual dep...

Quantum effects in small-capacitance high temperature superconducting tunneling junctions

Metallic adhesion in atomic-size junctions.

We report high resolution simultaneous measurements of electrical conductance and force gradient between two sharp gold tips as their separation is varied from the tunneling distance to atomic-size contact. The use of atomically sharp tips minimizes van der Waals interaction, making it possible to identify the short-range metallic adhesion contribution to the total force.