| In a brief talk, I will discuss work in collaboration with Tetsuo Haneguri and my student Marianna Maltseva, on quasiparticle interference scattering off pinned vortices, imaged by scanning tunnelling spectroscopy. QPI experiments show that when vortices are introduced, a spectral weight transfer from gap-sign reversing to gap sign preserving scattering events takes place, that we can interpret in terms of Andreev scattering off pinned vortices. The high momentum transfer indicates fluctuations in the gap on length scales much shorter than the vortex core size. I will introduce our model for this physics and discuss how it relates to "two gaps" and the concept of "big fat fast vortices" first introduced by Ioffe and Millis. |
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