Nature and Raman signatures of the Higgs amplitude mode in the coexisting superconducting and charge-density-wave state

Article

关键词: DEPENDENT SUPERCONDUCTIVITY;    COLLECTIVE MODES;    GAP EXCITATIONS;    SCATTERING;    SPECTROSCOPY;    TRANSITION;    2H-NBSE2;   

DOI  :  10.1103/PhysRevB.90.224515

来源: SCIE

【 摘 要 】

We investigate the behavior of the Higgs (amplitude) mode when superconductivity emerges on a preexisting charge-density-wave state. We show that the weak overdamped square-root singularity of the amplitude fluctuations in a standard BCS superconductor is converted in a sharp, undamped power-law divergence in the coexisting state, reminiscent of the Higgs behavior in Lorentz-invariant theories. This effect reflects in a strong superconducting resonance in the Raman spectra, both for an electronic and a phononic mechanism leading to the Raman visibility of the Higgs. In the latter case, our results are relevant to the interpretation of the Raman spectra measured experimentally in NbSe2.

【 授权许可】

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