Origin of Superconductivity and Latent Charge Density Wave in NbS2

Christoph Heil, Samuel Poncé, Henry Lambert, Martin Schlipf, Elena Roxana Margine, Feliciano Giustino

Research output: Contribution to journalLetterResearchpeer-review

Abstract

We elucidate the origin of the phonon-mediated superconductivity in 2H-NbS2 using the ab initio anisotropic Migdal-Eliashberg theory including Coulomb interactions. We demonstrate that superconductivity is associated with Fermi surface hot spots exhibiting an unusually strong electron-phonon interaction. The electron-lattice coupling is dominated by low-energy anharmonic phonons, which place the system on the verge of a charge density wave instability. We also provide definitive evidence for two-gap superconductivity in 2H-NbS2, and show that the low- and high-energy peaks observed in tunneling spectra correspond to the Γ- and K-centered Fermi surface pockets, respectively. The present findings call for further efforts to determine whether our proposed mechanism underpins superconductivity in the whole family of metallic transition metal dichalcogenides.
Original languageEnglish
Article number087003
Number of pages6
JournalPhysical Review Letters
Volume119
Issue number8
DOIs
Publication statusPublished - 24 Aug 2017
Externally publishedYes

Keywords

  • Superconductivity
  • Charge density waves
  • Electron-phonon coupling
  • Transition-metal dichalcogenides
  • First principles calculations

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    Heil, C., Poncé, S., Lambert, H., Schlipf, M., Margine, E. R., & Giustino, F. (2017). Origin of Superconductivity and Latent Charge Density Wave in NbS2. Physical Review Letters, 119(8), [087003]. https://doi.org/10.1103/PhysRevLett.119.087003