Superconducting Diode Effect in Quantum Spin Hall Insulator-based Josephson Junctions

Fuente: arXiv
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Autores principales: Scharf, Benedikt, Kochan, Denis, Matos-Abiague, Alex
Formato: Preprint
Publicado: 2024
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author Scharf, Benedikt
Kochan, Denis
Matos-Abiague, Alex
author_facet Scharf, Benedikt
Kochan, Denis
Matos-Abiague, Alex
contents The superconducting diode effect (SDE) is a magneto-electric phenomenon where an external magnetic field imparts a non-zero center-of-mass momentum to Cooper pairs, either facilitating or hindering the flow of supercurrent depending on its direction. We propose that quantum spin Hall insulator (QSHI)-based Josephson junctions can serve as versatile platforms for non-dissipative electronics exhibiting the SDE when triggered by a phase bias and an out-of-plane magnetic field. By computing the contributions from Andreev bound states and the continuum of quasi-particle states, we provide both numerical and analytical results scrutinizing various aspects of the SDE, including its quality Q-factor. The maximum value of the $Q$-factor is found to be universal at low (zero) temperatures, which ties its origin to underlying topological properties that are independent of the junction's specific details. As the magnetic field increases, the SDE diminishes due to the closing of the induced superconducting gap caused by orbital effects. To observe the SDE, the QSHI-based Josephson junction must be designed so that its edges are transport-wise non-equivalent. Additionally, we explore the SDE in a more exotic yet realistic scenario, where the fermionic ground-state parity of the Josephson junction remains conserved while driving a current. In this 4$π$-periodic situation, we predict an enhancement of the SDE compared to its 2$π$-periodic, parity-unconstrained counterpart.
format Preprint
id arxiv_https___arxiv_org_abs_2406_08669
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Superconducting Diode Effect in Quantum Spin Hall Insulator-based Josephson Junctions
Scharf, Benedikt
Kochan, Denis
Matos-Abiague, Alex
Superconductivity
The superconducting diode effect (SDE) is a magneto-electric phenomenon where an external magnetic field imparts a non-zero center-of-mass momentum to Cooper pairs, either facilitating or hindering the flow of supercurrent depending on its direction. We propose that quantum spin Hall insulator (QSHI)-based Josephson junctions can serve as versatile platforms for non-dissipative electronics exhibiting the SDE when triggered by a phase bias and an out-of-plane magnetic field. By computing the contributions from Andreev bound states and the continuum of quasi-particle states, we provide both numerical and analytical results scrutinizing various aspects of the SDE, including its quality Q-factor. The maximum value of the $Q$-factor is found to be universal at low (zero) temperatures, which ties its origin to underlying topological properties that are independent of the junction's specific details. As the magnetic field increases, the SDE diminishes due to the closing of the induced superconducting gap caused by orbital effects. To observe the SDE, the QSHI-based Josephson junction must be designed so that its edges are transport-wise non-equivalent. Additionally, we explore the SDE in a more exotic yet realistic scenario, where the fermionic ground-state parity of the Josephson junction remains conserved while driving a current. In this 4$π$-periodic situation, we predict an enhancement of the SDE compared to its 2$π$-periodic, parity-unconstrained counterpart.
title Superconducting Diode Effect in Quantum Spin Hall Insulator-based Josephson Junctions
topic Superconductivity
url https://arxiv.org/abs/2406.08669