Pairing gaps near ferromagnetic quantum critical points

Article

关键词: SPIN-FERMION MODEL;    2-DIMENSIONAL SYSTEMS;    PHASE-TRANSITIONS;    RENORMALIZATION;    SUPERCONDUCTORS;    STATE;    ORDER;   

DOI  :  10.1103/PhysRevB.91.064507

来源: SCIE

【 摘 要 】

We address the quantum-critical behavior of two-dimensional itinerant ferromagnetic systems described by spin-fermion models in which fermions interact with close-to-critical bosonic modes. We consider Heisenberg ferromagnets, Ising ferromagnets, and the Ising nematic transition. Mean-field theory close to the quantum critical point predicts a superconducting gap with spin-triplet symmetry for the ferromagnetic systems and a singlet gap for the nematic scenario. Studying fluctuations in this ordered phase using a nonlinear sigma model, we find that these fluctuations are not suppressed by any small parameter. As a result, we find that a superconducting quasi-long-range order is still possible in the Ising-like models but long-range order is destroyed in Heisenberg ferromagnets.

【 授权许可】

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