Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 53: Poster Session: Superconductivity 1

TT 53.11: Poster

Wednesday, March 22, 2017, 15:00–19:00, P2-OG2

Detecting sign-changing superconducting gap in LiFeAs using quasiparticle interference — •Dustin Altenfeld¹, Peter J. Hirschfeld², Igor I. Mazin³, and Ilya Eremin¹ — ¹Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum, Germany — ²Department of Physics, University of Florida, Gainesville, Florida 32611, USA — ³Code 6393, Naval Research Laboratory, Washington, DC 20375, USA

We present quasiparticle interference (QPI) measurement in Fe-based superconductors as a robust way of determining the superconducting gap sign structure in experiment. We show that the bias dependence of the signed symmetrized and antisymmetrized QPI maps are useful to obtain a characteristic signature of a gap sign change or lack thereof, starting from two-band model up to ab initio based band structure calculation. The experimental realization of the suggested method was successfully realized in FeSe, where a sign changing gap sign structure was identified. We provide a motivation for the application to the LiFeAs compounds.