Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 3: Superconductivity: Properties and Electronic Structure I
TT 3.8: Vortrag
Montag, 12. März 2018, 11:30–11:45, H 0110
Hidden nesting as the origin of strong electron-phonon coupling — •Philipp Kurzhals, Frank Weber, Rolf Heid, and John-Paul Castellan — Institute for Solid-State Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany
We report a combined inelastic neutron scattering and density-functional theory investigation of a phonon anomaly in the superconductor YNi2B2C assigned to strong electron-phonon coupling.
Band structure calculations indicate that the Fermi surface in the material is not nested in the sense that there is no singularity in the electronic joint density of states at the wavevector qanom=(0.55,0,0) that could define the phonon anomaly.
We measured the evolution of the strong-coupling phonon mode in a volume of reciprocal space around qanom to unravel the momentum dependence of electron-phonon coupling expressed in the softening and broadening of single phonon modes and compared it to predictions of ab-initio lattice dynamical calculations.
Our combined results hint at a hybrid approach, in which a small enhancement of the nesting properties is boosted by a concomitant increase of the electron-phonon coupling matrix elements at the same wavevector q.