Experimental realization of SQUIDs with topological insulator junctions

TL;DR

This paper reports the successful fabrication and characterization of dc SQUIDs using topological insulator Bi$_2$Te$_3$ with superconducting Nb leads, demonstrating controllable properties and potential for Majorana fermion detection.

Contribution

It presents the first reproducible fabrication of topological insulator-based dc SQUIDs with observed magnetic flux modulation matching design expectations.

Findings

Clear critical current modulation with magnetic field

Voltage-flux periodicity of $\

Reproducible fabrication process for topological insulator SQUIDs

Abstract

We demonstrate topological insulator (Bi$_2$Te$_3$) dc SQUIDs, based on superconducting Nb leads coupled to nano-fabricated Nb-Bi$_2$Te$_3$-Nb Josephson junctions. The high reproducibility and controllability of the fabrication process allows the creation of dc SQUIDs with parameters that are in agreement with design values. Clear critical current modulation of both the junctions and the SQUID with applied magnetic fields have been observed. We show that the SQUIDs have a periodicity in the voltage-flux characteristic of $\Phi_0$, of relevance to the ongoing pursuit of realizing interferometers for the detection of Majorana fermions in superconductor- topological insulator structures.