We report experimental evidences for the observation of the superconducting amplitude mode, so-called `Higgs' mode in the charge density wave superconductor 2H-NbSe2 using Raman scattering. By comparing 2H-NbSe2 and its iso-structural partner 2H-NbS2 which shows superconductivity but lacks the charge density wave order, we demonstrate that the superconducting mode in 2H-NbSe2 owes its spectral weight to the presence of the coexisting charge density wave order. In addition, temperature dependent measurements in 2H-NbSe2 show a full spectral weight transfer from the charge density wave mode to the superconducting mode upon entering the superconducting phase. Both observations are fully consistent with a superconducting amplitude mode or Higgs mode.
@article{arxiv.1401.1025,
title = {Amplitude `Higgs' mode in 2H-NbSe2 Superconductor},
author = {M. -A. Méasson and Y. Gallais and M. Cazayous and B. Clair and P. Rodière and L. Cario and A. Sacuto},
journal= {arXiv preprint arXiv:1401.1025},
year = {2015}
}
Comments
Accepted for publication in Phys. Rev. B Rapid Com. 5 pages with 3 figures