Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 59: Superconductivity: Fe-based Superconductors - FeSe and others
TT 59.8: Vortrag
Donnerstag, 23. März 2017, 11:30–11:45, HSZ 103
Tunneling spectroscopy and long wavelength quasiparticle interference in LiFeAs — •Z. Sun1, P. K. Nag1, S. Sykora1, S. Borensiko1, D. Baumman1, R. Kappenburger1, R. Beck1, S. Wurmehl1, B. Büchner1,2,3, and C. Hess1,3 — 1Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, 01069 Dresden — 2Institute for Solid State Physics, TU Dresden, 01069 Dresden — 3Center for Transport and Devices, TU Dresden, 01069 Dresden
We want present large-scale scanning tunneling spectroscopic map results on LiFeAs, especially focusing on the small momentum quasiparticle scatterings, where not much attention have been paid to previously. At the superconducting state, two particle-hole symmetric features are observed in the quasiparticle interference pattern: i) a large gap with a size of about 10 meV at 6.7 K; ii) ingap scatterings with small momentum transfer q close to zero. The evolution of the large gap size with temperature shows a mean field order parameter-like behavior with a critical temperature at Tc. For the large gap, we think that it reflects multiple scattering effects. And for the ingap particle-hole symmetric scatterings, we argue that they are due to the local variation of the superconducting order parameter caused by the defects and are related to Andreev reflection.