Spin-polarized Andreev molecules and anomalous nonlocal Josephson effects in altermagnetic junctions

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Mondal, Sayan, Cayao, Jorge
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866910042254475264
author Mondal, Sayan
Cayao, Jorge
author_facet Mondal, Sayan
Cayao, Jorge
contents Altermagnetism has emerged as a promising ingredient for realizing nontrivial Josephson phases, but so far explored in single Josephson junctions. In this work, we consider the coherent coupling of two Josephson junctions with spin-singlet $s$-wave superconductivity and demonstrate that $d$-wave altermagnetism gives rise to spin-polarized Andreev molecules due to the hybridization of Andreev bound states of each junction when the coupling is weak. Interestingly, these spin-polarized Andreev molecules induce an anomalous nonlocal Josephson effect, where the current flow across one Josephson junction due to phase changes across the other junction develops $0-π$ and $ϕ_{0}$ transitions originating from altermagnetism. Furthermore, the nonlocal Josephson current carried by spin-polarized Andreev molecules exhibits nonreciprocal critical currents, enabling a nonlocal Josephson diode effect whose polarity is tunable by the altermagnetic strength and right phase. Our findings put forward altermagnetism as a promising arena for designing nonlocal spin Josephson phenomena.
format Preprint
id arxiv_https___arxiv_org_abs_2603_04954
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spin-polarized Andreev molecules and anomalous nonlocal Josephson effects in altermagnetic junctions
Mondal, Sayan
Cayao, Jorge
Superconductivity
Mesoscale and Nanoscale Physics
Altermagnetism has emerged as a promising ingredient for realizing nontrivial Josephson phases, but so far explored in single Josephson junctions. In this work, we consider the coherent coupling of two Josephson junctions with spin-singlet $s$-wave superconductivity and demonstrate that $d$-wave altermagnetism gives rise to spin-polarized Andreev molecules due to the hybridization of Andreev bound states of each junction when the coupling is weak. Interestingly, these spin-polarized Andreev molecules induce an anomalous nonlocal Josephson effect, where the current flow across one Josephson junction due to phase changes across the other junction develops $0-π$ and $ϕ_{0}$ transitions originating from altermagnetism. Furthermore, the nonlocal Josephson current carried by spin-polarized Andreev molecules exhibits nonreciprocal critical currents, enabling a nonlocal Josephson diode effect whose polarity is tunable by the altermagnetic strength and right phase. Our findings put forward altermagnetism as a promising arena for designing nonlocal spin Josephson phenomena.
title Spin-polarized Andreev molecules and anomalous nonlocal Josephson effects in altermagnetic junctions
topic Superconductivity
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2603.04954