Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Electronic Structure and Spin-Orbit Interaction II

O 55.10: Vortrag

Mittwoch, 13. März 2013, 18:15–18:30, H42

Visualizing Anderson Localization of Non-Interacting Electrons — Fabian Zinser¹, Maurits W. Haverkort¹, Sune N. P. Wissing², Anke B. Schmidt², Markus Donath², Klaus Kern¹, and •Christian R. Ast¹ — ¹MPI für Festkörperforschung, 70569 Stuttgart — ²Physikalisches Institut, Westfälische Wilhelms-Universität Münster, 48149 Münster

Randomness destroys translational invariance resulting in exponential spatial localization of wave functions through quantum interference. This effect — known as Anderson localization — is a universal property of waves, which has been observed directly in light and matter. In electron systems, Anderson localization has been studied mostly indirectly in transport experiments through metal-insulator transitions or conductance fluctuations. This complicates theoretical descriptions as, e. g., calculating the conductance remains a challenging task despite highly sophisticated models. Using the Bi_xPb_1−x/Ag(111) mixed surface alloy, we go beyond averaged quantities both in theory and experiment. We measure simultaneously chemical composition and local electronic structure linking experiment and theory on the most fundamental level: we demonstrate the atomically resolved observation of spatial wave function localization for a mixed surface alloy — a purely two-dimensional electron system in a static disordered potential. We then use the chemical composition as the structural input for the “original” real space Anderson tight-binding model which allows us to directly compare the locally resolved wave functions in experiment and theory with remarkable agreement.