Current-induced dynamics in carbon atomic contacts

Publication: Research - peer-reviewJournal article – Annual report year: 2012

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Current-induced dynamics in carbon atomic contacts. / Lu, Jing Tao; Gunst, Tue; Brandbyge, Mads; Hedegård, Per.

In: Beilstein Journal of Nanotechnology, Vol. 2, No. 1, 2011, p. 814-823.

Publication: Research - peer-reviewJournal article – Annual report year: 2012

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Author

Lu, Jing Tao; Gunst, Tue; Brandbyge, Mads; Hedegård, Per / Current-induced dynamics in carbon atomic contacts.

In: Beilstein Journal of Nanotechnology, Vol. 2, No. 1, 2011, p. 814-823.

Publication: Research - peer-reviewJournal article – Annual report year: 2012

Bibtex

@article{9b11f4cddba64d60bf06ca40b93f453b,
title = "Current-induced dynamics in carbon atomic contacts",
author = "Lu, {Jing Tao} and Tue Gunst and Mads Brandbyge and Per Hedegård",
year = "2011",
doi = "10.3762/bjnano.2.90",
volume = "2",
number = "1",
pages = "814--823",
journal = "Beilstein Journal of Nanotechnology",

}

RIS

TY - JOUR

T1 - Current-induced dynamics in carbon atomic contacts

A1 - Lu,Jing Tao

A1 - Gunst,Tue

A1 - Brandbyge,Mads

A1 - Hedegård,Per

AU - Lu,Jing Tao

AU - Gunst,Tue

AU - Brandbyge,Mads

AU - Hedegård,Per

PY - 2011

Y1 - 2011

N2 - Background: The effect of electric current on the motion of atoms still poses many questions, and several mechanisms are at play. Recently there has been focus on the importance of the current-induced nonconservative forces (NC) and Berry-phase derived forces (BP) with respect to the stability of molecular-scale contacts. Systems based on molecules bridging electrically gated graphene electrodes may offer an interesting test-bed for these effects. Results: We employ a semi-classical Langevin approach in combination with DFT calculations to study the current-induced vibrational dynamics of an atomic carbon chain connecting electrically gated graphene electrodes. This illustrates how the device stability can be predicted solely from the modes obtained from the Langevin equation, including the current-induced forces. We point out that the gate offers control of the current, independent of the bias voltage, which can be used to explore current-induced vibrational instabilities due the NC/BP forces. Furthermore, using tight-binding and the Brenner potential we illustrate how Langevin-type molecular-dynamics calculations including the Joule heating effect for the carbon-chain systems can be performed. Molecular dynamics including current-induced forces enables an energy redistribution mechanism among the modes, mediated by anharmonic interactions, which is found to be vital in the description of the electrical heating. Conclusion: We have developed a semiclassical Langevin equation approach that can be used to explore current-induced dynamics and instabilities. We find instabilities at experimentally relevant bias and gate voltages for the carbon-chain system. © 2011 Lü et al.

AB - Background: The effect of electric current on the motion of atoms still poses many questions, and several mechanisms are at play. Recently there has been focus on the importance of the current-induced nonconservative forces (NC) and Berry-phase derived forces (BP) with respect to the stability of molecular-scale contacts. Systems based on molecules bridging electrically gated graphene electrodes may offer an interesting test-bed for these effects. Results: We employ a semi-classical Langevin approach in combination with DFT calculations to study the current-induced vibrational dynamics of an atomic carbon chain connecting electrically gated graphene electrodes. This illustrates how the device stability can be predicted solely from the modes obtained from the Langevin equation, including the current-induced forces. We point out that the gate offers control of the current, independent of the bias voltage, which can be used to explore current-induced vibrational instabilities due the NC/BP forces. Furthermore, using tight-binding and the Brenner potential we illustrate how Langevin-type molecular-dynamics calculations including the Joule heating effect for the carbon-chain systems can be performed. Molecular dynamics including current-induced forces enables an energy redistribution mechanism among the modes, mediated by anharmonic interactions, which is found to be vital in the description of the electrical heating. Conclusion: We have developed a semiclassical Langevin equation approach that can be used to explore current-induced dynamics and instabilities. We find instabilities at experimentally relevant bias and gate voltages for the carbon-chain system. © 2011 Lü et al.

KW - Semiclassical Langevin equation

KW - Current-induced forces

KW - Molecular contacts

KW - Carbon-nanoelectronics

KW - Nanoscale Joule heating

U2 - 10.3762/bjnano.2.90

DO - 10.3762/bjnano.2.90

JO - Beilstein Journal of Nanotechnology

JF - Beilstein Journal of Nanotechnology

IS - 1

VL - 2

SP - 814

EP - 823

ER -