eta collective mode as A(1g) Raman resonance in cuprate superconductors

Article

关键词: CHARGE-DENSITY-WAVE;    NEUTRON-SCATTERING;    FERMI-SURFACE;    ORDER;    EXCITATIONS;    PSEUDOGAP;    PHASE;    STATE;    GAP;    FLUCTUATIONS;   

DOI  :  10.1103/PhysRevB.93.024515

来源: SCIE

【 摘 要 】

We discuss the possible existence of a spin singlet excitation with charge +/- 2 (eta mode) originating the A(1g) Raman resonance in cuprate superconductors. This eta mode relates the d-wave superconducting singlet pairing channel to a d-wave charge channel. We show that the eta boson forms a particle-particle bound state below the 2 Delta threshold of the particle-hole continuum where Delta is the maximum d-wave gap. Within a generalized random phase approximation and Bethe-Salpeter approximation study, we find that this mode has energies similar to the resonance observed with inelastic neutron scattering below the superconducting (SC) coherent peak at 2 Delta in various SC cuprate compounds. We show that it is a very good candidate for the resonance observed in Raman scattering below the 2 Delta peak in the A(1g) symmetry. Since the eta mode sits in the S = 0 channel, it may be observable via Raman, x-ray, or electron energy loss spectroscopy probes.

【 授权许可】

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