Gate electrostatics and quantum capacitance in ballistic graphene device

Jose Caridad*, Stephen R. Power, Artsem Shylau, Lene Gammelgaard, Antti-Pekka Jauho, Peter Bøggild

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

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 (< 1 nm 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 2 classical electrostatics but also to quantum mechanical effects. We show that such quantum capacitance contribution, occurring due to the low density of states (DOS) 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 twodimensional (2D) electronic system confined by a hard-wall potential and are important for understanding the electronic structure and device applications of conducting 2D materials.
Original languageEnglish
Article number195408
JournalPhysical Review B (Condensed Matter and Materials Physics)
Volume99
Issue number19
Number of pages7
ISSN1098-0121
DOIs
Publication statusPublished - 2019

Cite this

@article{e866730a32554d0b8e79e7ee3ce378c8,
title = "Gate electrostatics and quantum capacitance in ballistic graphene device",
abstract = "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 (< 1 nm 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 2 classical electrostatics but also to quantum mechanical effects. We show that such quantum capacitance contribution, occurring due to the low density of states (DOS) 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 twodimensional (2D) electronic system confined by a hard-wall potential and are important for understanding the electronic structure and device applications of conducting 2D materials.",
author = "Jose Caridad and Power, {Stephen R.} and Artsem Shylau and Lene Gammelgaard and Antti-Pekka Jauho and Peter B{\o}ggild",
year = "2019",
doi = "10.1103/PhysRevB.99.195408",
language = "English",
volume = "99",
journal = "Physical Review B (Condensed Matter and Materials Physics)",
issn = "1098-0121",
publisher = "American Physical Society",
number = "19",

}

Gate electrostatics and quantum capacitance in ballistic graphene device. / Caridad, Jose; Power, Stephen R.; Shylau, Artsem; Gammelgaard, Lene; Jauho, Antti-Pekka; Bøggild, Peter.

In: Physical Review B (Condensed Matter and Materials Physics), Vol. 99, No. 19, 195408, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Gate electrostatics and quantum capacitance in ballistic graphene device

AU - Caridad, Jose

AU - Power, Stephen R.

AU - Shylau, Artsem

AU - Gammelgaard, Lene

AU - Jauho, Antti-Pekka

AU - Bøggild, Peter

PY - 2019

Y1 - 2019

N2 - 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 (< 1 nm 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 2 classical electrostatics but also to quantum mechanical effects. We show that such quantum capacitance contribution, occurring due to the low density of states (DOS) 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 twodimensional (2D) electronic system confined by a hard-wall potential and are important for understanding the electronic structure and device applications of conducting 2D materials.

AB - 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 (< 1 nm 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 2 classical electrostatics but also to quantum mechanical effects. We show that such quantum capacitance contribution, occurring due to the low density of states (DOS) 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 twodimensional (2D) electronic system confined by a hard-wall potential and are important for understanding the electronic structure and device applications of conducting 2D materials.

U2 - 10.1103/PhysRevB.99.195408

DO - 10.1103/PhysRevB.99.195408

M3 - Journal article

VL - 99

JO - Physical Review B (Condensed Matter and Materials Physics)

JF - Physical Review B (Condensed Matter and Materials Physics)

SN - 1098-0121

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