Driving the field-free Josephson diode effect using Kagome Mott insulator barriers

Fuente: arXiv
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Main Authors: Dubbelman, Michiel P., Wu, Heng, Aretz, Joost, Wang, Yaojia, Pasco, Chris M., Zhao, Yuzhou, Kyrk, Trent M., Yang, Jihui, Xu, Xiaodong, McQueen, Tyrel M., Roesner, Malte, Ali, Mazhar N.
Format: Preprint
Published: 2025
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author Dubbelman, Michiel P.
Wu, Heng
Aretz, Joost
Wang, Yaojia
Pasco, Chris M.
Zhao, Yuzhou
Kyrk, Trent M.
Yang, Jihui
Xu, Xiaodong
McQueen, Tyrel M.
Roesner, Malte
Ali, Mazhar N.
author_facet Dubbelman, Michiel P.
Wu, Heng
Aretz, Joost
Wang, Yaojia
Pasco, Chris M.
Zhao, Yuzhou
Kyrk, Trent M.
Yang, Jihui
Xu, Xiaodong
McQueen, Tyrel M.
Roesner, Malte
Ali, Mazhar N.
contents Josephson junctions (JJs), devices consisting of two superconductors separated by a barrier, are of great technological importance, being a cornerstone of quantum information processing. Classical understanding of superconductor-insulator-superconductor JJs is that conventional insulator's properties, other than magnetism, do not significantly influence the junction's behavior. However, recent work on quantum material (QM) JJs - using Mott insulator Nb3Br8 - resulted in magnetic field-free non-reciprocal superconductivity, termed the Josephson diode effect (JDE), implying the QM's intrinsic properties can modulate superconductivity in non-trivial ways. To date, the underlying mechanism and dependence of the JDE on correlation strength (U/t) has not been elucidated. Here we fabricate QMJJs using correlated Kagome insulators with varying U/t, Nb3X8 (X=Cl, Br, I), observing a decreasing trend of the field-free JDE with Nb3Cl8 reaching ~48% efficiency, Nb3Br8 ~6%, and Nb3I8 having no discernible JDE, matching the trend of decreasing U/t from Cl to I and suggesting correlation in insulators drives the field-free JDE.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17099
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Driving the field-free Josephson diode effect using Kagome Mott insulator barriers
Dubbelman, Michiel P.
Wu, Heng
Aretz, Joost
Wang, Yaojia
Pasco, Chris M.
Zhao, Yuzhou
Kyrk, Trent M.
Yang, Jihui
Xu, Xiaodong
McQueen, Tyrel M.
Roesner, Malte
Ali, Mazhar N.
Superconductivity
Strongly Correlated Electrons
Josephson junctions (JJs), devices consisting of two superconductors separated by a barrier, are of great technological importance, being a cornerstone of quantum information processing. Classical understanding of superconductor-insulator-superconductor JJs is that conventional insulator's properties, other than magnetism, do not significantly influence the junction's behavior. However, recent work on quantum material (QM) JJs - using Mott insulator Nb3Br8 - resulted in magnetic field-free non-reciprocal superconductivity, termed the Josephson diode effect (JDE), implying the QM's intrinsic properties can modulate superconductivity in non-trivial ways. To date, the underlying mechanism and dependence of the JDE on correlation strength (U/t) has not been elucidated. Here we fabricate QMJJs using correlated Kagome insulators with varying U/t, Nb3X8 (X=Cl, Br, I), observing a decreasing trend of the field-free JDE with Nb3Cl8 reaching ~48% efficiency, Nb3Br8 ~6%, and Nb3I8 having no discernible JDE, matching the trend of decreasing U/t from Cl to I and suggesting correlation in insulators drives the field-free JDE.
title Driving the field-free Josephson diode effect using Kagome Mott insulator barriers
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2512.17099