Nonequilibrium spin-splitter effect in altermagnet superconductor hybrids

Fuente: arXiv
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Auteurs principaux: Kokkeler, Tim, Heikkilä, Tero T., Bergeret, F. Sebastian
Format: Preprint
Publié: 2025
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author Kokkeler, Tim
Heikkilä, Tero T.
Bergeret, F. Sebastian
author_facet Kokkeler, Tim
Heikkilä, Tero T.
Bergeret, F. Sebastian
contents We study the nonequilibrium spin-splitter effect in superconducting altermagnets and superconductor altermagnet hybrids by computing the alternating spin current and edge the spin density in the presence of an alternating electric field. We show that while in the normal state the effect is not sensitive to the field frequency, in the superconducting state, there is a strong effect for frequencies on the scale of $Δ_0$ or lower. We contrast the effect to the spin accumulation induced by the spin-Hall effect, by showing that for the altermagnet spin-splitter effect the out-of-phase spin density does not diverge in the adiabatic limit. This difference is attributed to the absence of any equilibrium spin-splitter effect in altermagnets. In fact, the out-of-phase component vanishes below the gap excitation frequency $2Δ_0$, because below this frequency the absence of dissipation and the behavior of the system under time-reversal directly determine the relative phase between the charge current, spin current, and spin accumulation. The nonequilibrium effect can be tuned by external parameters like temperature. In fact, it has a nonmonotonic temperature dependence, taking its largest value for temperatures around $0.8T_{c}$. The value at this temperature can be significantly larger than the normal state spin density or the low temperature spin density. Thus, besides using the nonequilibrium spin-splitter effect to identify altermagnets, its tunability makes it also suitable for applications.
format Preprint
id arxiv_https___arxiv_org_abs_2510_11355
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nonequilibrium spin-splitter effect in altermagnet superconductor hybrids
Kokkeler, Tim
Heikkilä, Tero T.
Bergeret, F. Sebastian
Superconductivity
We study the nonequilibrium spin-splitter effect in superconducting altermagnets and superconductor altermagnet hybrids by computing the alternating spin current and edge the spin density in the presence of an alternating electric field. We show that while in the normal state the effect is not sensitive to the field frequency, in the superconducting state, there is a strong effect for frequencies on the scale of $Δ_0$ or lower. We contrast the effect to the spin accumulation induced by the spin-Hall effect, by showing that for the altermagnet spin-splitter effect the out-of-phase spin density does not diverge in the adiabatic limit. This difference is attributed to the absence of any equilibrium spin-splitter effect in altermagnets. In fact, the out-of-phase component vanishes below the gap excitation frequency $2Δ_0$, because below this frequency the absence of dissipation and the behavior of the system under time-reversal directly determine the relative phase between the charge current, spin current, and spin accumulation. The nonequilibrium effect can be tuned by external parameters like temperature. In fact, it has a nonmonotonic temperature dependence, taking its largest value for temperatures around $0.8T_{c}$. The value at this temperature can be significantly larger than the normal state spin density or the low temperature spin density. Thus, besides using the nonequilibrium spin-splitter effect to identify altermagnets, its tunability makes it also suitable for applications.
title Nonequilibrium spin-splitter effect in altermagnet superconductor hybrids
topic Superconductivity
url https://arxiv.org/abs/2510.11355