Surface Junction in Bi$_2$Sr$_2$CaCu$_2$O$_{8+d}$ Single Crystals

TL;DR

This study investigates the surface junction properties of Bi$_2$Sr$_2$CaCu$_2$O$_{8+d}$ single crystals, revealing evidence of second order supercurrent through microwave-induced steps, supporting theoretical predictions.

Contribution

The paper provides experimental evidence of second order supercurrent in the surface junction of Bi$_2$Sr$_2$CaCu$_2$O$_{8+d}$, confirming theoretical models with microwave step observations.

Findings

Observation of half-integral microwave-induced steps.

Detection of integral steps with resistive shunting.

Evidence supporting second order supercurrent as per Tanaka's theory.

Abstract

As nature junction geometry of the d-wave cuprate superconductor/insulator/the mixture of s-wave and d-wave cuprate superconductor, the upmost surface junction of intrinsic Josephson junction stack fabricated on Bi$_2$Sr$_2$CaCu$_2$O$_{8+d}$ single crystals was measured and discussed. We successfully observed half-integral microwave induced steps as well as integral steps with resistively shunting technology, which shows the evidence of second order supercurrent, consistent with Tanaka's theory.