Tomographic mapping of the hidden dimension in quasi-particle interference

TL;DR

This paper introduces a tomographic method to analyze quasiparticle interference imaging, enabling the reconstruction of three-dimensional electronic structures in materials with non-pronounced anisotropy.

Contribution

It develops a formalism for quasiparticle tomography that extracts 3D electronic structure and orbital information from QPI data in isotropic materials.

Findings

QPI signals are dominated by in-plane scattering vectors from 3D electronic structures.

The formalism successfully reconstructs the 3D electronic structure of galena.

The method reveals orbital character contributions in the electronic bands.

Abstract

Quasiparticle interference (QPI) imaging is well established to study the low-energy electronic structure in strongly correlated electron materials with unrivalled energy resolution. Yet, being a surface-sensitive technique, the interpretation of QPI only works well for anisotropic materials, where the dispersion in the direction perpendicular to the surface can be neglected and the quasiparticle interference is dominated by a quasi-2D electronic structure. Here, we explore QPI imaging of galena, a material with an electronic structure that does not exhibit pronounced anisotropy. We find that the quasiparticle interference signal is dominated by scattering vectors which are parallel to the surface plane however originate from bias-dependent cuts of the 3D electronic structure. We develop a formalism for the theoretical description of the QPI signal and demonstrate how this quasiparticle tomography can be used to obtain information about the 3D electronic structure and orbital character of the bands.