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Gapped Nearly Free-Standing Graphene on an SiC(0001) Substrate Induced by Manganese Atoms
Appl. Sci. Converg. Technol. 2018;27:90-94
Published online September 30, 2018;  https://doi.org/10.5757/ASCT.2018.27.5.90
© 2018 The Korean Vacuum Society.

Jinwoong Hwanga, Ji-Eun Leea, Minhee Kanga, Byeong-Gyu Parkb, Jonathan Denlingerc, Sung-Kwan Moc, and Choongyu Hwanga,*

aDepartment of Physics, Pusan National University, Busan 46241, Korea
bPohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 37673, Korea
cAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
Correspondence to: E-mail: ckhwang@pusan.ac.kr
Received September 17, 2018; Revised September 28, 2018; Accepted September 29, 2018.
Abstract
The electron band structure of manganese-adsorbed graphene on an SiC(0001) substrate has been studied using angle-resolved photoemission spectroscopy. Upon introducing manganese atoms, the conduction band of graphene, that is observed in pristine graphene indicating intrinsic electron-doping by the substrate, completely disappears and the valence band maximum is observed at 0.4 eV below Fermi energy. At the same time, the slope of the valence band decreases by the presence of manganese atoms, approaching the electron band structure calculated using the local density approximation method. The former provides experimental evidence of the formation of nearly free-standing graphene on an SiC substrate, concomitant with a metal-to-insulator transition. The latter suggests that its electronic correlations are efficiently screened, suggesting that the dielectric property of the substrate is modified by manganese atoms and indicating that electronic correlations in grpahene can also be tuned by foreign atoms. These results pave the way for promising device application using graphene that is semiconducting and charge neutral.
Keywords : Graphene, SiC, Manganese, Free-standing, Metal-to-insulator transition, Angle-resolved photoemission spectroscopy


September 2018, 27 (5)