Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 30: Poster: Proximity Effects in Epitaxial Graphene
O 30.5: Poster
Dienstag, 19. März 2024, 12:30–14:30, Poster A
Simulations of electronic transport in inhomogeneous intercalated graphene systems — •Tim Güldenpfennig, Markus Gruschwitz, and Christoph Tegenkamp — Institut für Physik, Technische Universität Chemnitz
Pb intercalated buffer layer on 4H-SiC(0001) creates charge neutral quasi-freestanding graphene [1]. The presence of a densely packed Pb monolayer at the interface triggers interest in transport experiments hunting for a superconductivity or proximity-induced SOC in graphene. However, nanoscale measurements sensitively depend on the local distribution of conductive phases. Multiprobe-STM reveal an 1D to 2D transition with increasing tip spacing s on a single terrace. Angle dependent measurements show a discrete anisotropy behavior. We approach the separation of contributing conductive phases by finite element simulations using COMSOL multiphysics. Our model - based on dimensions measured by SEM and XSW - consists of a series of 3.5 µm wide terraces separated by 100 nm wide barriers of alternating conductivities, respectively. Starting with the measured terrace conductivity (600 kS/m) repeated optimization provide best agreement for R(s) for σterrace=500 kS/m and σbarrier=200 S/m. Applied in a square angle dependent setup the model also recreates the discrete anisotropy behavior. On larger scale, barrier defects yield a continuous but smaller anisotropy. Finally, we explore the separation of two T-dependent phases by varying the conductivity levels in the model based on reference measurements at 30 K and RT. [1] Adv. Mater. Interfaces 10, 2300471 (2023); [2] Materials 14, 7706 (2021)