Quantum transport theory for unconventional magnets: Interplay of altermagnetism and p-wave magnetism with superconductivity

Abstract

We present a quantum transport theory for generic magnetic metals, in which magnetism occurs predominantly due to exchange interactions, such as ferromagnets, antiferromagnets, altermagnets and p-wave magnets. Our theory is valid both for the normal and the superconducting state. We derive the effective low-energy action for each of these materials, where the spin space groups are used to determine the form of the tensor coefficients appearing in the action. The transport equations, which are obtained as the saddle point equations of this action, describe a wider range of phenomena than the usual quasiclassical equations. In ferromagnets, in addition to the usual exchange field and spin relaxation effects, we identify a spin-dependent renormalization of the diffusion coefficient, which provides a description of spinpolarized currents in both the normal and superconducting equal spin-triplet states. In the normal state, our equations provide a complete description of the spin-splitting effect in diffusive systems, recently predicted in ideal clean altermagnets. In the superconducting state, our equations predict a proximity induced magnetization, the appearance of a spontaneous magnetic moment in hybrid superconductor-altermagnet systems. The distribution and polarization direction of this magnetic moment depend on the symmetry of the structure, thus measurements of such polarization reveal the underlying microscopic symmetry of the altermagnet. Finally, for inversionsymmetry broken antiferromagnets, such as the p-wave magnet, we show that spin-galvanic effects which are distinguishable from the spin-galvanic effect induced by spin-orbit coupling only in the superconducting state. Besides these examples, our model applies to arbitrary magnetic systems, providing a complete theory for nonequilibrium transport in diffusive nonconventional magnets at arbitrary temperatures.

arXiv comment16 pages, 3 figures

References in corpus (62)

• Proximity effects in superconductor-ferromagnet heterostructures
• Magnetic effects at the interface between nonmagnetic oxides
• Odd Triplet Superconductivity and Related Phenomena in Superconductor-Ferromagnet Structures
• Superconducting Spintronics
• Altermagnetism: spin-momentum locked phase protected by non-relativistic symmetries
• Long-range effects in superconductor-ferromagnet structures
• Efficient Electrical Spin-Splitter Based on Non-Relativistic Collinear Antiferromagnetism
• Symmetry and Topology in Superconductors - Odd-frequency pairing and edge states -
• Quasiclassical Green's function approach to mesoscopic superconductivity
• Altermagnetism: Exploring New Frontiers in Magnetism and Spintronics
• Direct observation of altermagnetic band splitting in CrSb thin films
• Keldysh technique and non-linear sigma-model: basic principles and applications
• Single particle Green's functions and interacting topological insulators
• Bottom-up design of spin-split and reshaped electronic band structures in spin-orbit-coupling free antiferromagnets: Procedure on the basis of augmented multipoles
• Long range triplet Josephson effect through a ferromagnetic trilayer
• Spin-group symmetry in magnetic materials with negligible spin-orbit coupling
• Electron--electron Interactions in Disordered Metals: Keldysh Formalism
• Colloquium: Nonequilibrium effects in superconductors with a spin-splitting field
• Enumeration and representation theory of spin space groups
• Spin Space Groups: Full Classification and Applications
• Enumeration of spin-space groups: Towards a complete description of symmetries of magnetic orders
• Spontaneous Antisymmetric Spin Splitting in Noncollinear Antiferromagnets without Spin-Orbit Coupling
• Majorana corner modes and tunable patterns in an altermagnet heterostructure
• Anomalous current in diffusive ferromagnetic Josephson junctions
• Keldysh action for disordered superconductors
• Minimal Models and Transport Properties of Unconventional $p$-Wave Magnets
• Effective field theory of the disordered Weyl semimetal
• Tail States in a Superconductor with Magnetic Impurities
• Schwinger-Keldysh Approach to Disordered and Interacting Electron Systems: Derivation of Finkelstein's Renormalization Group Equations
• Theory of the strongly disordered Weyl semimetal
• $\phi$ Josephson junction induced by altermagnetism
• Structure, control, and dynamics of altermagnetic textures
• Theory of Tunneling Spectroscopy in Unconventional $p$-wave Magnet-Superconductor Hybrid Structures
• Josephson effect and odd-frequency pairing in superconducting junctions with unconventional magnets
• Superconductors with Magnetic Impurities: Instantons and Sub-gap States
• Generalized quasiclassical theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets
• Transport across junctions of altermagnets with normal metals and ferromagnets
• Néel proximity effect at antiferromagnet/superconductor interfaces
• Quasiclassical theory of superconducting spin-splitter effects and spin-filtering via altermagnets
• Mechanism of antisymmetric spin polarization in centrosymmetric multiple-$Q$ magnets based on bilinear and biquadratic spin cross products
• Keldysh Nonlinear Sigma Model for a Free-Fermion Gas under Continuous Measurements
• Berezinskii-Kosterlitz-Thouless transition in homogeneously disordered superconducting films
• Classification of pair symmetries in superconductors with unconventional magnetism
• Symmetry invariants and classes of quasiparticles in magnetically ordered systems having weak spin-orbit coupling
• Impurity-induced Friedel oscillations in altermagnets and $p$-wave magnets
• Response theory of the ergodic many-body delocalized phase: Keldysh Finkel'stein sigma models and the 10-fold way
• The Crystallographic Spin Point Groups and their Representations
• Proximity effect in superconductor/antiferromagnet hybrids: Neel triplets and impurity suppression of superconductivity
• Nonlinear $\sigma$ model for disordered superconductors
• Nonlinear $\sigma$-model for disordered systems with intrinsic spin-orbit coupling
• Quasiclassical expressions for the free energy of superconducting systems
• Coexistence of $p$-wave magnetism and superconductivity
• Thermal Transport and Wiedemann-Franz Law in the Disordered Fermi Liquid
• Algorithm for spin symmetry operation search
• Tail States in Disordered Superconductors with Magnetic Impurities: the Unitarity Limit
• Spin-Transfer Torque in Altermagnets with Magnetic Textures
• Quasiclassical theory for antiferromagnetic metals
• P-wave magnets
• Non-linear sigma model with particle-hole asymmetry for the disordered two-dimensional electron gas
• Superconducting Order Parameters in Spin Space Groups: Methodology and Application
• A Theory of Anisotropic Magnetoresistance in Altermagnets and Its Applications
• Altermagnets and beyond: Nodal magnetically-ordered phases

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• Interplay between Superconductivity and Altermagnetism in Disordered Materials and Heterostructures
• Phonon-enhanced optical spin-conductivity and spin-splitter effect in altermagnets
• Sub-spin-flop switching of a fully compensated antiferromagnet by magnetic field
• Spin-Valley Locking and Pure Spin-Triplet Superconductivity in Noncollinear Antiferromagnets Proximitized to Conventional Superconductors
• Time reversal reserved spin valve and spin transistor based on unconventional $p$-wave magnets