Quantized Electron Transport Through Graphene Nanoconstrictions

Here, the quantization of Dirac fermions in lithographically defined graphene nanoconstrictions is studied. Quantized conductance is observed in single nanoconstrictions fabricated on top of a thin hexamethyldisilazane layer over a Si/SiO2 wafer. This nanofabrication method allows to obtain well def...

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Bibliographic Details
Published in:Physica status solidi. A, Applications and materials science Applications and materials science, 2018-10, Vol.215 (19), p.n/a
Main Authors: Clericò, Vito, Delgado‐Notario, Juan A., Saiz‐Bretín, Marta, Hernández Fuentevilla, Cristina, Malyshev, Andrey V., Lejarreta, Juan D., Diez, Enrique, Domínguez‐Adame, Francisco
Format: Article
Language:English
Subjects:
Computer simulation
Electron transport
Fermions
Graphene
Measurement
Nanofabrication
nanostructures
quantized conductance
Quantum interference effects
Resistance
Roughness
Silicon dioxide
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Summary:Here, the quantization of Dirac fermions in lithographically defined graphene nanoconstrictions is studied. Quantized conductance is observed in single nanoconstrictions fabricated on top of a thin hexamethyldisilazane layer over a Si/SiO2 wafer. This nanofabrication method allows to obtain well defined edges in the nanoconstrictions, thus reducing the effects of edge roughness on the conductance. The occurrence of ballistic transport is proved and several size quantization plateaus are identified in the conductance at low temperature. Experimental data and numerical simulations show good agreement, demonstrating that the smoothening of the plateaus is not related to edge roughness but to quantum interference effects. Graphene nanoconstrictions fabricated on top of a thin hexamethyldisilazane layer exhibit excellent crystalline quality with well‐defined edges. Transport measurements show clear evidence of quantized conductance as a function of the electron density, but the plateaus turn out to be rather smooth. Numerical simulations on clean samples show good agreement with the experimental results. Therefore, the smoothening of the plateaus is not related to edge roughness but rather to quantum interference effects.
ISSN:1862-6300
1862-6319
DOI:10.1002/pssa.201701065