Quasiclassical theory of superconducting spin-splitter effects and spin-filtering via altermagnets

Abstract

Conducting altermagnets have recently emerged as intriguing materials supporting strongly spin-polarized currents without magnetic stray fields. We demonstrate that altermagnets enable three key functionalities, merging superconductivity and spintronics. The first prediction is a controllable supercurrent-induced edge magnetization, which acts like a dissipationless spin-splitter effect. The second and third predictions are a Cooper pair spin-splitter and a filtering effect, respectively. These effects allow for spatial separation of triplet pairs with opposite spin-polarizations and spin-selective tunneling of Cooper pairs. We derive a quasiclassical theory with associated boundary conditions that describe these phenomena and explain how they can be experimentally verified. Our results open a new path for spatial control of spin signals via triplet Cooper pairs using hybrid superconductor-altermagnet devices.

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• Minimal Models and Transport Properties of Unconventional $p$-Wave Magnets
• Superconducting phenomena in systems with unconventional magnets
• Altermagnetism in the layered intercalated transition metal dichalcogenide CoNb${}_4$Se${}_8$
• Unconventional p-wave and finite-momentum superconductivity induced by altermagnetism through the formation of Bogoliubov Fermi surface
• Altermagnetism and superconductivity in a multiorbital t-J model
• Impurity-induced Friedel oscillations in altermagnets and $p$-wave magnets
• Nonlinear Superconducting Magnetoelectric Effect
• Topological responses from gapped Weyl points in 2D altermagnets
• Spin-polarized Specular Andreev Reflections in Altermagnets
• Quantum transport theory for unconventional magnets: Interplay of altermagnetism and p-wave magnetism with superconductivity
• Conditions for orbital selective altermagnetism in Sr${}_2$RuO${}_4$: tight binding model, similarities with cuprates and implications on superconductivity
• Thermodynamic properties of a superconductor interfaced with an altermagnet
• Nonlinear Piezomagnetic Effects in $g$-wave Altermagnets
• Light-induced Floquet spin-triplet Cooper pairs in unconventional magnets
• Visualization of spin-splitter effect in altermagnets via non-equilibrium Green functions on a lattice
• Quantization of spin circular photogalvanic effect in altermagnetic Weyl semimetals
• Engineering subgap states in superconductors by the symmetry of altermagnetism
• Viscoelastic tensor and hydrodynamics of altermagnets
• Interplay between Superconductivity and Altermagnetism in Disordered Materials and Heterostructures
• Analysis of Spin Current Generation by Elastic Waves in $f$-wave Altermagnets
• Spin triplet pairing by suppressing altermagnetism
• Spin-Valley Locking and Pure Spin-Triplet Superconductivity in Noncollinear Antiferromagnets Proximitized to Conventional Superconductors
• Phonon-enhanced optical spin-conductivity and spin-splitter effect in altermagnets