Charge transfer between van der Waals coupled metallic 2D layers

Fuente: arXiv
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Main Authors: Matta, Bharti, Rosenzweig, Philipp, Polley, Craig, Starke, Ulrich, Küster, Kathrin
Format: Preprint
Published: 2025
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author Matta, Bharti
Rosenzweig, Philipp
Polley, Craig
Starke, Ulrich
Küster, Kathrin
author_facet Matta, Bharti
Rosenzweig, Philipp
Polley, Craig
Starke, Ulrich
Küster, Kathrin
contents Van der Waals heterostructures have become a rapidly growing field in condensed matter research, offering a platform to engineer novel quantum systems by stacking different two-dimensional (2D) materials. A diverse range of material combinations, including hexagonal boron nitride, transition metal dichalcogenides and graphene, with electronic properties spanning from insulating to semiconducting, metallic, and semimetallic, have been explored to tune the properties of these heterostacks. However, understanding the interactions and charge transfer between the stacked layers remains challenging, particularly when more than two layers are involved. In this study, we investigate the charge transfer in a potassium-adlayer/graphene/lead-monolayer heterostructure stacked on a SiC substrate. Using synchrotron-based angle-resolved photoemission spectroscopy, we analyze the band structure of each layer, focusing on the charge transfer from K to the underlying 2D layers. Since K forms a $(2 \times 2)$ overlayer with respect to graphene, the amount of charge carriers donated by K can be determined. Our findings reveal that adsorption of K not only leads to a significant $n$-doping of the adjacent graphene layer but also to an electron transfer into the Pb monolayer. Remarkably, $\approx 44\%$ of the electrons donated by the K adlayer are transferred into its second nearest neighbouring layer, i.e. Pb, while $\approx 56\%$ remain in the graphene.
format Preprint
id arxiv_https___arxiv_org_abs_2505_07382
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Charge transfer between van der Waals coupled metallic 2D layers
Matta, Bharti
Rosenzweig, Philipp
Polley, Craig
Starke, Ulrich
Küster, Kathrin
Mesoscale and Nanoscale Physics
Materials Science
Van der Waals heterostructures have become a rapidly growing field in condensed matter research, offering a platform to engineer novel quantum systems by stacking different two-dimensional (2D) materials. A diverse range of material combinations, including hexagonal boron nitride, transition metal dichalcogenides and graphene, with electronic properties spanning from insulating to semiconducting, metallic, and semimetallic, have been explored to tune the properties of these heterostacks. However, understanding the interactions and charge transfer between the stacked layers remains challenging, particularly when more than two layers are involved. In this study, we investigate the charge transfer in a potassium-adlayer/graphene/lead-monolayer heterostructure stacked on a SiC substrate. Using synchrotron-based angle-resolved photoemission spectroscopy, we analyze the band structure of each layer, focusing on the charge transfer from K to the underlying 2D layers. Since K forms a $(2 \times 2)$ overlayer with respect to graphene, the amount of charge carriers donated by K can be determined. Our findings reveal that adsorption of K not only leads to a significant $n$-doping of the adjacent graphene layer but also to an electron transfer into the Pb monolayer. Remarkably, $\approx 44\%$ of the electrons donated by the K adlayer are transferred into its second nearest neighbouring layer, i.e. Pb, while $\approx 56\%$ remain in the graphene.
title Charge transfer between van der Waals coupled metallic 2D layers
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2505.07382