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Multi-atom quasiparticle scattering interference for superconductor energy-gap symmetry determination

Sharma, R.; Kreisel, A.; Sulangi, M. A.; Böker, J.; Kostin, A.; Allan, M. P.; Eisaki, H.; Böhmer, Anna E.; Canfield, P. C.; Eremin, I.; Séamus Davis, J. C.; Hirschfeld, P. J.; Sprau, P. O.

Complete theoretical understanding of the most complex superconductors requires a detailed knowledge of the symmetry of the superconducting energy-gap Δ$\frac{α}{k}$, for all momenta k on the Fermi surface of every band α. While there are a variety of techniques for determining |Δ$\frac{α}{k}$|, no general method existed to measure the signed values of Δ$\frac{α}{k}$. Recently, however, a technique based on phase-resolved visualization of superconducting quasiparticle interference (QPI) patterns, centered on a single non-magnetic impurity atom, was introduced. In principle, energy-resolved and phase-resolved Fourier analysis of these images identifies wavevectors connecting all k-space regions where Δ$\frac{α}{k}$ has the same or opposite sign. But use of a single isolated impurity atom, from whose precise location the spatial phase of the scattering interference pattern must be measured, is technically difficult. Here we introduce a generalization of this approach for use with multiple impurity atoms, and demonstrate its validity by comparing the Δ$\frac{α}{k}$ it generates to the Δ$\frac{α}{k}$ determined from single-atom scattering in FeSe where s± energy-gap symmetry is established. ... mehr

Zugehörige Institution(en) am KIT Institut für Quantenmaterialien und -technologien (IQMT)
Publikationstyp Forschungsbericht/Preprint
Publikationsdatum 12.01.2021
Sprache Englisch
Identifikator KITopen-ID: 1000129377
Nachgewiesen in arXiv
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