TY - JOUR
T1 - Origin of Superconductivity and Latent Charge Density Wave in NbS2
AU - Heil, Christoph
AU - Poncé, Samuel
AU - Lambert, Henry
AU - Schlipf, Martin
AU - Margine, Elena Roxana
AU - Giustino, Feliciano
PY - 2017/8/24
Y1 - 2017/8/24
N2 - 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.
AB - 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.
KW - Superconductivity
KW - Charge density waves
KW - Electron-phonon coupling
KW - Transition-metal dichalcogenides
KW - First principles calculations
UR - https://arxiv.org/abs/1708.01487
U2 - 10.1103/PhysRevLett.119.087003
DO - 10.1103/PhysRevLett.119.087003
M3 - Letter
SN - 1079-7114
VL - 119
JO - Physical Review Letters
JF - Physical Review Letters
IS - 8
M1 - 087003
ER -