Universität zu Köln

Struzzi, C., Praveen, C. S., Scardamaglia, M., Verbitskiy, N. I., Fedorov, A. V., Weinl, M., Schreck, M., Gruneis, A., Piccinin, S., Fabris, S. and Petaccia, L. (2016). Controlled thermodynamics for tunable electron doping of graphene on Ir(111). Physical review B, 94 (8). 085427. APS Physics. ISSN 2469-9950

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Abstract

The electronic properties and surface structures of K-doped graphene supported on Ir(111) are characterized as a function of temperature and coverage by combining low-energy electron diffraction, angle-resolved photoemission spectroscopy, and density functional theory (DFT) calculations. Deposition of K on graphene at room temperature (RT) yields a stable (√3 × √3) R30° surface structure having an intrinsic electron doping that shifts the graphene Dirac point by ED = 1.30 eV below the Fermi level. Keeping the graphene substrate at 80 K during deposition generates instead a (2 × 2) phase, which is stable until full monolayer coverage. Further deposition of K followed by RT annealing develops a double-layer K-doped graphene that effectively doubles the K coverage and the related charge transfer, as well as maximizing the doping level (ED = 1.61 eV). The measured electron doping and the surface reconstructions are rationalized by DFT calculations. These indicate a large thermodynamic driving force for K intercalation below the graphene layer. The electron doping and Dirac point shifts calculated for the different structures are in agreement with the experimental measurements. In particular, the K4s bands are shown to be sensitive to both the K intercalation and periodicity and are therefore suggested as a fingerprint for the location and ordering of the K dopants.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Struzzi, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Praveen, C. S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scardamaglia, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Verbitskiy, N. I. UNSPECIFIED UNSPECIFIED UNSPECIFIED Fedorov, A. V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Weinl, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schreck, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gruneis, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Piccinin, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Fabris, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Petaccia, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-81524
DOI:	10.1103/PhysRevB.94.085427
Journal or Publication Title:	Physical review B
Volume:	94
Number:	8
Page Range:	085427
Date:	25 August 2016
Publisher:	APS Physics
ISSN:	2469-9950
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	Natural sciences and mathematics Physics
Funders:	European Cooperation in Science and Technology (COST) Action MP0901 (STSM Grant), Fonds pour la Formation a la Recherche dans l’Industrie et dans l’Agriculture ` (FRIA), Austrian Science Fund (FWF) Project No. P27769-N20—‘Electron and Spin Correlation in Nano Carbon-Metal Hybrids’, Russian Science Foundation (Grant No. 14-13-00747), e European Research Council (ERC) Grant No. 648589—‘SUPER-2D’
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/8152