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arXiv · 1902.07459

Quantum nanoconstrictions fabricated by cryo-etching in encapsulated graphene

Vito Clericò·Juan Antonio Delgado-Notario·Marta Saiz-Bretín·Andrey V. Malyshev·Yahya M. Meziani·Pedro Hidalgo·Bianchi Méndez·Mario Amado·Francisco Domínguez-Adame·Enrique Diez
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Abstract

More than a decade after the discovery of graphene, ballistic transport in nanostructures based on this intriguing material still represents a challenging field of research in two-dimensional electronics. The presence of rough edges in nanostructures based on this material prevents the appearance of truly ballistic electron transport as theo\-re\-tically predicted and, therefore, not well-developed plateaus of conductance have been revealed to date. In this work we report on a novel implementation of the cryo-etching method, which enabled us to fabricate graphene nanoconstrictions encapsulated between hexagonal boron nitride thin films with unprecedented control of the structure edges. High quality smooth nanometer-rough edges are characterized by atomic force microscopy and a clear correlation between low roughness and the existence of well-developed quantized conductance steps with the concomitant occurrence of ballistic transport is found at low temperature. In par\-ti\-cu\-lar, we come upon exact 2$e^{2}/h$ quantization steps of conductance at zero magnetic field due to size quantization, as it has been theoretically predicted for truly ballistic electron transport through graphene nanoconstrictions.

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Vito Clericò, Juan Antonio Delgado-Notario, Marta Saiz-Bretín, Andrey V. Malyshev, Yahya M. Meziani, Pedro Hidalgo, Bianchi Méndez, Mario Amado, Francisco Domínguez-Adame, Enrique Diez. 2019-02-20. Quantum nanoconstrictions fabricated by cryo-etching in encapsulated graphene. https://doi.org/10.1038/s41598-019-50098-z

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