A Theory of Anisotropic Magnetoresistance in Altermagnets and Its Applications

Abstract

Altermagnets, a newly discovered class of magnets, integrate the advantages of both ferromagnets and antiferromagnets, such as enabling anomalous transport without stray fields and supporting ultrafast spin dynamics, offering exciting opportunities for spintronics. A key challenge in altermagnetic spintronics is the efficient reading and writing of information by switching the Neel vector orientations to represent binary 0 and 1. Here, we develop a microscopic theory of the magnetoresistance effect in altermagnets and propose that magnetoresistance anisotropy can serve as an effective mechanism for the electrical readout of the Neel vector. Our theory describes a two-step charge-spin-charge conversion process governed by the interplay between spin splitting and spin Hall effects: a longitudinal electric field induces transverse drift spin currents, which induce significant spin accumulation at the boundaries, generating a diffusive spin current that is converted back into a longitudinal charge current. By switching the Neel vector, a substantial change in magnetoresistance, akin to giant magnetoresistance in ferromagnets, is realized, enabling an electrically readable altermagnetic memory. Our microscopic theory provides deeper insights into the fundamental physics of the magnetoresistance effect in altermagnets and offers valuable guidance for designing next-generation ultradense and ultrafast spintronic devices based on altermagnetism.

8 pages, 3 figures

References in corpus (21)

• Altermagnetism: spin-momentum locked phase protected by non-relativistic symmetries
• Theory of spin Hall magnetoresistance
• Observation of spin splitting torque in a collinear antiferromagnet RuO2
• Giant and tunneling magnetoresistance effects from anisotropic and valley-dependent spin-momentum interactions in antiferromagnets
• Altermagnetism: Exploring New Frontiers in Magnetism and Spintronics
• Direct observation of altermagnetic band splitting in CrSb thin films
• Spontaneous anomalous Hall effect arising from an unconventional compensated magnetic phase in a semiconductor
• Intrinsic nonlinear Hall effect in antiferromagnetic tetragonal CuMnAs
• Large band-splitting in $g$-wave type altermagnet CrSb
• Exchange interaction between single magnetic adatoms
• Nonmagnetic Ground State in RuO${}_2$ Revealed by Muon Spin Rotation
• Three-dimensional mapping of the altermagnetic spin splitting in CrSb
• X-ray Magnetic Circular Dichroism in Altermagnetic $\alpha$-MnTe
• Absence of altermagnetic spin splitting character in rutile oxide RuO${}_2$
• Phase-shifted Andreev levels in an altermagnet Josephson junction
• Observation of Spin Splitting in Room-Temperature Metallic Antiferromagnet CrSb
• Electrically Controllable Crystal Chirality Magneto-Optical Effects in Collinear Antiferromagnets
• Topological Weyl Altermagnetism in CrSb
• Observation of surface Fermi arcs in altermagnetic Weyl semimetal CrSb
• Spin-Splitting Magnetoresistance in Altermagnetic RuO2 Thin Films
• Scaling Behavior of Magnetoresistance and Hall Resistivity in Altermagnet CrSb

Cited by in corpus (1)

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