Dresden 2020 – wissenschaftliches Programm
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O 100.4: Vortrag
Donnerstag, 19. März 2020, 11:15–11:30, REC C 213
Scanning Tunneling Microscopy of Sub-Surface Atomic Structure of the Phase Change Material GeSb2Te4 Enabled via Surface Antiresonances — •Philipp Küppers1, Peter Schmitz2, Marcus Liebmann1, Albert Ratajczak3, Hilde Hardtdegen4, Detlev Grützmacher3, Riccardo Mazzarello2, and Markus Morgenstern1 — 1II. Inst. Phys. B and JARA-FIT, RWTH Aachen University — 2Institut für Theoretische Festkörperphysik, RWTH Aachen University — 3Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI 9) — 4Forschungszentrum Jülich GmbH, Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons (ERC-2)
The detailed atomic structure of phase change materials including its disorder is crucial for the understanding of many of its key features. A detailed mapping of the atomic disorder is challenging by standard approaches such as transmission electron microscopy, atom probe tomography or scanning tunneling microscopy. The latter suffers from the fact that the surface is covered by the well ordered Te layer. Here, we show by comparison of scanning tunneling spectroscopy and density functional theory data that details of the subsurface layer consisting of Ge, Sb and vacancies can be mapped by exploiting states that are suppressed towards the surface, so-called surface antiresonances. Probing such states becomes apparent as a honeycomb structure consisting of the Te layer and a significant contribution from the subsurface arrangement.