Graphene Tunable Transparency to Tunneling Electrons: A Direct Tool To Measure the Local Coupling.
The local interaction between graphene and a host substrate strongly determines the actual properties of the graphene layer. Here we show that scanning tunneling microscopy (STM) can selectively help to visualize either the graphene layer or the substrate underneath, or even both at the same time, providing a comprehensive picture of this coupling with atomic precision and high energy resolution. We demonstrate this for graphene on Cu(111). Our spectroscopic data show that, in the vicinity of the Fermi level, graphene π bands are well preserved presenting a small n-doping induced by Cu(111) surface state electrons. Such results are corroborated by Angle-Resolved Photoemission Spectra (ARPES) and Density Functional Theory with van der Waals (DFT + vdW) calculations. Graphene tunable transparency also allows the investigation of the interaction between the substrate and foreign species (such as atomic H or C vacancies) on the graphene layer. Our calculations explain graphene tunable transparency in terms of the rather different decay lengths of the graphene Dirac π states and the metal surface state, suggesting that it should apply to a good number of graphene/substrate systems.
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.|Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
Héctor
H
González-Herrero
Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain.|Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
Pablo
P
Pou
Centro de Física de Materiales (CSIC-UPV-EHU) and Materials Physics Center (MPC) , Manuel Lardizábal 5, E-20018 San Sebastián, Spain.
Jorge
J
Lobo-Checa
Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
Delia
D
Fernández-Torre
II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany.
Fabian
F
Craes
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.|II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany.
Antonio J
AJ
Martínez-Galera
CIC nanoGUNE , 20018 Donostia-San Sebastian, Spain.|Ikerbasque, Basque Foundation for Science , 48013 Bilbao, Spain.
Miguel M
MM
Ugeda
Centro de Física de Materiales (CSIC-UPV-EHU) and Materials Physics Center (MPC) , Manuel Lardizábal 5, E-20018 San Sebastián, Spain.|Ikerbasque, Basque Foundation for Science , 48013 Bilbao, Spain.
Martina
M
Corso
Centro de Física de Materiales (CSIC-UPV-EHU) and Materials Physics Center (MPC) , Manuel Lardizábal 5, E-20018 San Sebastián, Spain.|Donostia International Physics Center DIPC , E-20018 San Sebastián, Spain.|Departamento de Física Aplicada I, Universidad del País Vasco , E-20018 San Sebastián, Spain.
J Enrique
JE
Ortega
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.|Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
José M
JM
Gómez-Rodríguez
Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain.|Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
Rubén
R
Pérez
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid , E-28049 Madrid, Spain.|Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
Iván
I
Brihuega
ARPES; Cu(111); DFT; STM; electronic properties; graphene