Dresden 2020 – wissenschaftliches Programm
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TT 54.10: Vortrag
Donnerstag, 19. März 2020, 12:00–12:15, HSZ 201
One-Electron-Pocket Model of FeSe: Quasiparticle Interference — •Matthias Eschrig1,2, Luke C. Rhodes2,3,4, Matthew D. Watson4, and Timur K. Kim4 — 1Universität Greifswald, Germany — 2Royal Holloway, University of London, UK — 3University of St. Andrews, UK — 4Diamond Light Source, Harwell Campus, UK
The one-electron-pocket model of FeSe was introduced to account for experimental observations in angle-resoved photoemission (ARPES) experiments. Quasiparticle interference (QPI) measurements of FeSe, obtained via scanning tunneling microscopy, have previously been interpreted as being consistent with a theoretical model where the Fermi surface consists of one hole pocket and two electron pockets and exhibits a large difference in the quasiparticle weight of the dxz and dxy orbitals. On the contrary, orbital sensitive measurements from ARPES have been interpreted as being consistent with a model with roughly equivalent quasiparticle weights for the dxz and dyz orbitals, but with only one hole pocket and one electron pocket at the Fermi surface present. Here, we show that the second, one-electron-pocket, model also explains QPI experiments. We find, that it is important to apply a selection rule for QPI, that only electronic states with vanishing component of the Fermi velocity perpendicular to the scanning surface contribute to the interference pattern. By using a three-dimensional tight-binding model of FeSe, fit to ARPES measurements, we directly reproduce the experimental QPI results, within a T-matrix formalism. This unifying result for QPI and ARPES on FeSe also highlights the importance of selection rules for QPI experiments via STM.