Magnon-induced superconductivity in field-cooled spin-1/2 antiferromagnets

Abstract

If, during the preparation, an external magnetic field is applied upon cooling we say it has been field cooled. A novel mechanism for insulator-metal transition and superconductivity in field-cooled spin-1/2 antiferromagnets on bcc lattice is discussed. Applying a magnetic field along the sublattice B magnetization, we change the magnetic and transport properties of the material. There is a critical value Hcr1. When the magnetic field is below the critical one H<Hcr1 the prepared material is a spin-1/2 antiferromagnetic insulator. When H>Hcr1 the sublattice A electrons are delocalized and the material is metal. There is a second critical value Hcr2>Hcr1. When H=Hcr2, it is shown that the Zeeman splitting of the sublattice A electrons is zero and they do not contribute to the magnetization of the system. At this quantum partial order point (QPOP) the sublattice B transversal spin fluctuations (magnons) interact with sublattice A electrons inducing spin antiparallel p-wave superconductivity which coexists with magnetism. At zero temperature the magnetic moment of sublattice B electrons is maximal. Below the Néel temperature (TN) the gap is approximately constant with a small increase when the system approaches TN. It abruptly falls down to zero at temperatures above TN.

Source-reported materials — not catalogue approval

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