Controlled thermodynamics for tunable electron doping of graphene on Ir(111)

Autor(en)

C. Struzzi, C. S. Praveen, M. Scardamaglia, N. I. Verbitskiy, A. V. Fedorov, M. Weinl, M. Schreck, Alexander Grüneis, S. Piccinin, S. Fabris, L. Petaccia

Abstrakt

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=1.30eV 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=1.61eV). 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.

Organisation(en)

Elektronische Materialeigenschaften

Externe Organisation(en)

Elettra Sincrotrone Trieste, University of Mons , Consiglio Nazionale delle Ricerche, Scuola Internazionale Superiore di Studi Avanzati, Lomonosov Moscow State University (MSU), Universität zu Köln, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Saint Petersburg State University, Universität Augsburg

Journal

Physical Review B

Band

94

Anzahl der Seiten

10

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.94.085427

Publikationsdatum

08-2016

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik, 103009 Festkörperphysik

Schlagwörter

ASJC Scopus Sachgebiete

Electronic, Optical and Magnetic Materials, Condensed Matter Physics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/3e2c75ad-294e-408b-a97b-d69888bc8dd9