Gate electrostatics and quantum capacitance in ballistic graphene devices
Caridad, José M. (Danmarks Tekniske Universitet. Center for Nanostructured Graphene)
Power, Stephen R. (Institut Català de Nanociència i Nanotecnologia)
Shylau, Artsem A. (Danmarks Tekniske Universitet. Center for Nanostructured Graphene)
Gammelgaard, Lene (Danmarks Tekniske Universitet. Center for Nanostructured Graphene)
Jauho, Antti-Pekka (Danmarks Tekniske Universitet. Center for Nanostructured Graphene)
Bøggild, Peter (Danmarks Tekniske Universitet. Center for Nanostructured Graphene)

Fecha:	2019
Resumen:	We experimentally investigate the charge induction mechanism across gated, narrow, ballistic graphene devices with different degrees of edge disorder. By using magnetoconductance measurements as the probing technique, we demonstrate that devices with large edge disorder exhibit a nearly homogeneous capacitance profile across the device channel, close to the case of an infinitely large graphene sheet. In contrast, devices with lower edge disorder (<1nm roughness) are strongly influenced by the fringing electrostatic field at graphene boundaries, in quantitative agreement with theoretical calculations for pristine systems. Specifically, devices with low edge disorder present a large effective capacitance variation across the device channel with a nontrivial, inhomogeneous profile due not only to classical electrostatics but also to quantum mechanical effects. We show that such quantum capacitance contribution, occurring due to the low density of states across the device in the presence of an external magnetic field, is considerably altered as a result of the gate electrostatics in the ballistic graphene device. Our conclusions can be extended to any two-dimensional (2D) electronic system confined by a hard-wall potential and are important for understanding the electronic structure and device applications of conducting 2D materials.
Ayudas:	European Commission 785219 European Commission 665919
Derechos:	Aquest material està protegit per drets d'autor i/o drets afins. Podeu utilitzar aquest material en funció del que permet la legislació de drets d'autor i drets afins d'aplicació al vostre cas. Per a d'altres usos heu d'obtenir permís del(s) titular(s) de drets.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió sotmesa a revisió
Materia:	Device application ; External magnetic field ; Gate electrostatics ; Quantitative agreement ; Quantum capacitance ; Quantum mechanical effects ; Theoretical calculations ; Two Dimensional (2 D)
Publicado en:	Physical review B, Vol. 99, issue 19 (May 2019) , art. 195408, ISSN 2469-9969

DOI: 10.1103/PhysRevB.99.195408

Preprint 34 p, 4.0 MB

El registro aparece en las colecciones:
Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias > Institut Català de Nanociència i Nanotecnologia (ICN2)
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