Journal Article

Impurity effects of hydrogen and deuterium in vanadium nanoconstrictions

Islam, M S, Ueno, Y, Kawae, T, Takata, H, Hashizume, K, Inagaki, Y

2018

Overview

To study non-magnetic and magnetic impurity effects at the superconductor-normal metal interfaces, we have measured the differential conductance dI/dV for Josephson contacts made by vanadium (V) nanoconstrictions with a different amount of hydrogen (H) and deuterium (D) impurities, which are prepared by a mechanically controllable break junction (MCBJ) technique at low temperature. Below the superconducting transition temperature TC, we have found distinct peaks within and outside the gap, known as the sub-gap structure and an over-the-gap structure respectively, due to 5% concentration of atomic H and D on V nanocontact. Moreover, the temperature dependence of dI/dV spectra represents that both structures are survived until the critical temperature TC, which is consistent with the prediction of BCS energy gap. On the other hand, a very high concentrating phase (30atom%) behaves as a normal metal.

• Publisher: IOP Publishing
• Subject: Critical temperature / Deuterium / Energy gap / Impurities / Impurity effects / Low temperature / MCBJ / over-the-gap structure / Physics / sub-gap structure / Temperature dependence / Transition temperature / Vanadium