Ab Initio Theory of Fourier‐Transformed Quasiparticle Interference Maps and Application to the Topological Insulator Bi2Te3

The quasiparticle interference (QPI) technique is a powerful tool that allows to uncover the structure and properties of electronic structure of a material combined with scattering properties of defects at surfaces. Recently, this technique has been pivotal in proving the unique properties of the surface state of topological insulators which manifests itself in the absence of backscattering. Herein, a Green function‐based formalism is derived for the ab initio computation of Fourier‐transformed QPI images. The efficiency of the new implementation is shown at the examples of QPI that forms around magnetic and nonmagnetic defects at the Bi2Te3 surface. This method allows a deepened understanding of the scattering properties of topologically protected electrons off defects and is a useful tool in the study of quantum materials in the future. A Green function and T‐matrix‐based approach to simulate Fourier‐transformed quasiparticle interference (QPI) maps from first principles is derived. The new density‐functional‐based implementation is applied to QPI images for defects at the surface of the topological insulator Bi2Te3. This reveals the interplay of topological surface state electrons with time‐reversal breaking or conserving impurities.