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

T. Cea; L. Benfatto

doi:10.1103/PhysRevB.90.224515

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

T. Cea, L. Benfatto

DOI 10.1103/PhysRevB.90.224515 · Physical Review B

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Abstract

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.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
NbSe2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7	Pressure not reported	unknown
NbS2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown