Current Conservation in the Self-Consistent Josephson Junction

Fuente: arXiv
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Hauptverfasser: Krekels, Simon, Levajac, Vukan, Moors, Kristof, Simion, George, Sorée, Bart
Format: Preprint
Veröffentlicht: 2025
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_version_ 1866912643744268288
author Krekels, Simon
Levajac, Vukan
Moors, Kristof
Simion, George
Sorée, Bart
author_facet Krekels, Simon
Levajac, Vukan
Moors, Kristof
Simion, George
Sorée, Bart
contents Conventional treatments of Josephson junctions (JJs) are typically not current-conserving. In the mean-field BCS theory, current conservation is only guaranteed if the superconducting order parameter is treated self-consistently. We show that this requirement has significant consequences for the current-phase relation (CPR) in certain regimes, where the current density in the superconducting leads is non-negligible. To this end, we introduce a numerical method for the self-consistent treatment of the BdG equations with current conservation for quasi-1D superconductor-normal (metal)-superconductor (SNS) JJs. Our model incorporates a phase gradient of the order parameter in the leads, which is set to match the Josephson current through the weak link. We compare our method to standard, non-current-conserving approaches by calculating the CPR for SNS JJs while varying lengths and gate voltages controlling the normal metal. We show that current conservation has significant implications for the Josephson harmonics and can weaken or even reverse forward skewness of the CPR.
format Preprint
id arxiv_https___arxiv_org_abs_2505_09288
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Current Conservation in the Self-Consistent Josephson Junction
Krekels, Simon
Levajac, Vukan
Moors, Kristof
Simion, George
Sorée, Bart
Superconductivity
Mesoscale and Nanoscale Physics
Conventional treatments of Josephson junctions (JJs) are typically not current-conserving. In the mean-field BCS theory, current conservation is only guaranteed if the superconducting order parameter is treated self-consistently. We show that this requirement has significant consequences for the current-phase relation (CPR) in certain regimes, where the current density in the superconducting leads is non-negligible. To this end, we introduce a numerical method for the self-consistent treatment of the BdG equations with current conservation for quasi-1D superconductor-normal (metal)-superconductor (SNS) JJs. Our model incorporates a phase gradient of the order parameter in the leads, which is set to match the Josephson current through the weak link. We compare our method to standard, non-current-conserving approaches by calculating the CPR for SNS JJs while varying lengths and gate voltages controlling the normal metal. We show that current conservation has significant implications for the Josephson harmonics and can weaken or even reverse forward skewness of the CPR.
title Current Conservation in the Self-Consistent Josephson Junction
topic Superconductivity
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2505.09288