Charge-carrier-induced frequency renormalization, damping, and heating of vibrational modes in nanoscale junctions

Kristen Kaasbjerg, Tomas Novotny, Abraham Nitzan

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In nanoscale junctions the interaction between charge carriers and the local vibrations results in renormalization, damping, and heating of the vibrational modes. Herewe formulate a nonequilibrium Green’s function based theory
to describe such effects. Studying a generic junction model with an off-resonant electronic level, we find a strong bias dependence of the frequency renormalization and vibrational damping accompanied by pronounced nonlinear
vibrational heating in junctions with intermediate values of the coupling to the leads. Combining our theory with ab initio calculations, we furthermore show that the bias dependence of the Raman shifts and linewidths observed experimentally in an oligo(3)-phenylenevinylene (OPV3) junction [Ward et al., Nat. Nanotechnol. 6, 33 (2011)] may be explained by a combination of dynamic carrier screening and molecular charging.
Original languageEnglish
Article number239902
JournalPhysical Review B
Volume88
Issue number23
Number of pages5
ISSN0163-1829
DOIs
Publication statusPublished - 2013
Externally publishedYes

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