kz Selective Scattering within Quasiparticle Interference Measurements of FeSe

• Published in: Physical review letters Vol. 123; no. 21; p. 1
• Main Authors: Rhodes, Luke C, Watson, Matthew D, Kim, Timur K, Eschrig, Matthias
• Format: Journal Article
• Language: English
• Published: College Park American Physical Society 22-11-2019
• Subjects: Electron states; Electronic structure; Group velocity; Interference; Photoelectric emission; Scattering; Surface defects; Three dimensional models
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.123.216404

Quasiparticle interference (QPI) provides a wealth of information relating to the electronic structure of a material. However, it is often assumed that this information is constrained to two-dimensional electronic states. We show that this is not necessarily the case. For FeSe, a system dominated by surface defects, we show that it is actually all electronic states with negligible group velocity in the z axis that are contained within the experimental data. By using a three-dimensional tight-binding model of FeSe, fit to photoemission measurements, we directly reproduce the experimental QPI scattering dispersion, within a T-matrix formalism, by including both kz=0 and kz=π electronic states. This result unifies both tunnelling based and photoemission based experiments on FeSe and highlights the importance of kz within surface sensitive measurements of QPI.