Academic Affiliation: Leiden University, Netherlands

Research Area: Develop and use novel techniques for STM to investigate quantum matter.

Talk date: January 22, 2020

A strongly inhomogeneous superfluid in an iron-based superconductor

Although the possibility of spatial variations in the superfluid of unconventional, strongly correlated superconductors has been suggested, it is not known whether such inhomogeneities – if they exist – are driven by disorder, strong scattering, or other factors. In this talk I will show how we use Josephson scanning tunneling microscopy to reveal a strongly inhomogeneous superfluid in the iron-based superconductor FeTe_0.55Se_0.45. By simultaneously acquiring the topographic and electronic properties, we find that this inhomogeneity in the superfluid is not caused by structural disorder or strong inter-pocket scattering, and does not correlate with variations in the energy of the Cooper pair-breaking gap. Instead, we see a clear spatial correlation between superfluid density and the quasiparticle strength, defined as the height of the coherence peak, on a local scale. [1]

References:
[1] D. Cho*, K.M. Bastiaans* et al. Nature 571, 541 (2019)