The University of Dublin | Trinity College -- Ollscoil Átha Cliath | Coláiste na Tríonóide
Trinity's Access to Research Archive
Home :: Log In :: Submit :: Alerts ::

School of Physics >
Physics >
Physics (Scholarly Publications) >

Please use this identifier to cite or link to this item:

Title: Current-induced energy barrier suppression for electromigration from first principles
Name Grant Number

Author's Homepage:
Keywords: Condensed matter physics
Issue Date: 2011
Citation: Zhang, RX, Rungger, I, Sanvito, S, Hou, SM, Current-induced energy barrier suppression for electromigration from first principles, Physical Review B - Condensed Matter and Materials Physics, 84, 8, 2011, 085445
Series/Report no.: Physical Review B - Condensed Matter and Materials Physics
Abstract: We present an efficient method for evaluating current-induced forces in nanoscale junctions, which naturally integrates into the nonequilibrium Green's function formalism implemented within density functional theory. This allows us to perform dynamic atomic relaxation in the presence of an electric current while evaluating the current-voltage characteristics. The central idea consists of expressing the system energy density matrix in terms of Green's functions. To validate our implementation, we perform a series of benchmark calculations, both at zero and at finite bias. First we evaluate the current-induced forces acting over an Al nanowire and compare them with previously published results for fixed geometries. Then we perform structural relaxation of the same wires under bias and determine the critical voltage at which they break. We find that although a perfectly straight wire does not break at any of the voltages considered, a zigzag wire is more fragile and snaps at 1.4 V, with the Al atoms moving against the electron flow. The critical current density for the rupture is estimated to be 9.6 x 10(10) A/cm(2), in good agreement with the experimentally measured value of 5 x 10(10) A/cm(2). Finally, we demonstrate the capability of our scheme to tackle the electromigration problem by studying the current-induced motion of a single Si atom covalently attached to the sidewall of a (4,4) armchair single-walled carbon nanotube. Our calculations indicate that if Si is attached along the current path, then current-induced forces can induce migration. In contrast, if the bonding site is away from the current path, then the adatom remains stable regardless of the voltage. An analysis based on decomposing the total force into a wind and an electrostatic component, as well as on a detailed evaluation of the bond currents, shows that this remarkable electromigration phenomenon is due solely to the position-dependent wind force.
Description: PUBLISHED
Related links:
Appears in Collections:Physics (Scholarly Publications)

Files in This Item:

File Description SizeFormat
Current-induced energy barrier suppression for electromigration from first principles.pdfPublished (publisher's copy) - Peer Reviewed1.39 MBAdobe PDFView/Open

This item is protected by original copyright

Please note: There is a known bug in some browsers that causes an error when a user tries to view large pdf file within the browser window. If you receive the message "The file is damaged and could not be repaired", please try one of the solutions linked below based on the browser you are using.

Items in TARA are protected by copyright, with all rights reserved, unless otherwise indicated.


Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback