TY - JOUR

T1 - Unraveling the origin of local variations in the step resistance of epitaxial graphene on SiC: a quantitative scanning tunneling potentiometry study

AU - Sinterhauf, Anna

AU - Traeger, Georg A.

AU - Momeni, Davood

AU - Pierz, Klaus

AU - Schumacher, Hans Werner

AU - Wenderoth, Martin

N1 - Funding information: Financial support of the Deutsche Forschungsgemeinschaft (DFG) through project We 1889/13–1 is gratefully acknowledged. The preparation of the samples was funded by the Deutsche Forschungsgemeinschaft (DFG) under Germany's Excellence Strategy - EXC-2123 QuantumFrontiers - 390837967 .

PY - 2021/10/30

Y1 - 2021/10/30

N2 - By combining highly resolved Scanning Tunneling Potentiometry with the exceptional sample homogeneity of graphene on SiC epitaxially grown by polymer-assisted sublimation growth, we reveal local variations in the resistance associated with substrate steps. We quantify these variations and show that they are an intrinsic property of graphene on SiC. Furthermore, we trace back their origin to variations in the electronic structure of the interface and, thereby, demonstrate the crucial impact of intrinsic proximity effects in graphene on SiC. Moreover, we find a correlation of the step resistance with the local conductivity and show that at room temperature, the step resistance decreases with increasing local conductivity, whereas at low temperatures, it increases with increasing local conductivity. We attribute this inversion to an interplay between the reduction in electron-phonon scattering and potential scattering with decreasing temperature, and the efficiency of the built-up of an almost completely charge carrier depleted zone at the position of the substrate step.

AB - By combining highly resolved Scanning Tunneling Potentiometry with the exceptional sample homogeneity of graphene on SiC epitaxially grown by polymer-assisted sublimation growth, we reveal local variations in the resistance associated with substrate steps. We quantify these variations and show that they are an intrinsic property of graphene on SiC. Furthermore, we trace back their origin to variations in the electronic structure of the interface and, thereby, demonstrate the crucial impact of intrinsic proximity effects in graphene on SiC. Moreover, we find a correlation of the step resistance with the local conductivity and show that at room temperature, the step resistance decreases with increasing local conductivity, whereas at low temperatures, it increases with increasing local conductivity. We attribute this inversion to an interplay between the reduction in electron-phonon scattering and potential scattering with decreasing temperature, and the efficiency of the built-up of an almost completely charge carrier depleted zone at the position of the substrate step.

KW - Charge carrier depletion

KW - Epitaxial graphene/SiC

KW - Local-scale charge transport

KW - Localized defects

KW - Scanning tunneling potentiometry

KW - Substrate steps

UR - http://www.scopus.com/inward/record.url?scp=85113427628&partnerID=8YFLogxK

U2 - 10.1016/j.carbon.2021.08.050

DO - 10.1016/j.carbon.2021.08.050

M3 - Article

AN - SCOPUS:85113427628

VL - 184

SP - 463

EP - 469

JO - CARBON

JF - CARBON

SN - 0008-6223

ER -