Abstracts Book - IMRC 2018

• SA3-O004
STRONG ELECTRONIC MODULATION ASSISTED BY THE
INTERLAYER ROTATION ANGLE IN GRAPHENE/WS2
Francisco Sanchez Ochoa 1 , Cecilia Noguez 1 , Francisco Hidalgo 1
1 Universidad Nacional Autónoma de México, Solid state department, Instituto de Fisica,
Mexico.
A strong modulation on the electronic properties of graphene (G) interacting
with a two-dimensional (2D) tungsten disulfide (WS2) monolayer is found. This
modulation depends on the relative orientation between monolayers or
interlayer rotation angle. A systematic study was performed using density
functional theory and by unfolding band structure of the hybrid van der Waals
heterostructures. Here, the electronic structure is projected onto the original G
unit cell, such that, the changes in the electronic structure due to the interlayer
interaction can be easily analyzed. It is found at the Fermi level (EF) that the Dirac
cones keep their linear dispersion without the generation of a band gap,
independently of the interlayer rotation angle. However, below EF the band due
to carbon pz atomic orbitals are hybridized with those of WS2, which originates
mini gaps. Also, some resonances are observed that avoid the crossing between
G and WS2 bands. Our findings are in agreement with angle-resolved
photoelectron spectroscopy (ARPES) measurements, where mini gaps were
observed [1-3]. In conclusion, the control of the interlayer angle in hybrid 2D
vdW heterostructures is crucial to design new nanoelectronic and nanophotonic
devices, like thin film transistors and optical modulators with desired properties.
References:
1 Pierucci, D.; et al., Band Alignment and Minigaps in Monolayer MoS2-
Graphene van der Waals Heterostructures. Nano Lett. 2016, 16(7), 4054-4061.
2 Diaz, H. C.; et al., Direct Observation of Interlayer Hybridization and Dirac
Relativistic Carriers in Graphene/MoS2 van der Waals Heterostructures. Nano
Lett. 2015, 15(2), 1135-1140.
3 Le, N. B.; Huan, T. D.; Woods, L. M. Interlayer Interactions in van der Waals
Heterostructures: Electron and Phonon Properties. ACS Appl. Mater. Interfaces
2016, 8(9), 6286-6292.
Keywords: graphene, tungsten disulfie, mini-gaps
Presenting authors email: fsanchez@fisica.unam.mx