Interference, diffraction, and diode effects in superconducting array based on Bi0.8Sb1.2Te3 topological insulator

TL;DR

This paper demonstrates that superconducting arrays on topological insulators can act as highly sensitive magnetic sensors and exhibit diode effects due to their inherent asymmetry, drawing an analogy to optical diffraction and interference phenomena.

Contribution

It introduces a superconducting analogue to optical diffraction gratings using arrays on topological insulators, revealing enhanced sensitivity and diode behavior.

Findings

Array exhibits sharper critical current peaks than traditional SQUIDs.

Device functions as a sensitive absolute magnetic field sensor.

Array's asymmetry induces superconducting diode effects.

Abstract

It is a well known phenomenon in optics that spectroscopic resolution of a diffraction grating is much better compared to an interference device having just two slits, as in the Young's famous double-slit experiment. On the other hand, it is well known that a classical superconducting quantum interference device (SQUID) is analogous to the optical double-slit experiment. Here we report experiments and present a model describing a superconducting analogue to the diffraction grating, namely an array of superconducting islands positioned on a topological insulator (TI) film Bi0.8Sb1.2Te3. In the limit of extremely weak field, of the order of one vortex per the entire array, such devices exhibit a critical current peak that is much sharper than the analogous peak of an ordinary SQUID. Because of this, such arrays can be used as sensitive absolute magnetic field sensors. An important finding is that, due to the inherent asymmetry of such arrays, the device also acts as a superconducting diode.