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

Article

关键词: GROUND-STATES;    VALENCE-BOND;    MODEL;    FERROMAGNETISM;    ORDER;    FLUCTUATION;    COEXISTENCE;    DISORDER;    PEIERLS;   

DOI  :  10.1103/PhysRevB.96.214409

来源: SCIE

【 摘 要 】

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 H-cr1. When the magnetic field is below the critical one H < H-cr1 the prepared material is a spin-1/2 antiferromagnetic insulator. When H > H-cr1 the sublattice A electrons are delocalized and the material is metal. There is a second critical value H-cr2 > H-cr1. When H = H-cr2, 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 Neel temperature (T-N) the gap is approximately constant with a small increase when the system approaches T-N. It abruptly falls down to zero at temperatures above T-N.

【 授权许可】

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