New 'Altermagnetic' Phase Enables Large Spin Splitting Without Net Magnetization
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Altermagnetism is a recently predicted third elementary magnetic phase, distinct from conventional ferro- and antiferromagnetism, that enables lifting of Kramers spin degeneracy without net magnetization or broken inversion symmetry.
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Two mechanisms of altermagnetic lifting of Kramers degeneracy are demonstrated using ARPES in MnTe a "weak" mechanism enabled by spin-orbit coupling, and a "strong" non-relativistic mechanism.
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The strong altermagnetic mechanism causes large, eV-scale spin splitting comparable to that in non-centrosymmetric crystals, despite MnTe having an inversion center.
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SARPES confirms the alternating sign of spin polarization and large spin splitting outside the nodal planes as a signature of strong altermagnetic lifting of Kramers degeneracy.
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Realization of altermagnetic Kramers degeneracy lifting enriches spintronics, magnetoelectrics, topological matter and dissipationless electronics by removing limitations associated with net magnetization.