Current-induced phonon renormalization in molecular junctions

Meilin Bai, Clotilde S. Cucinotta, Zhuoling Jiang, Hao Wang, Yongfeng Wang, Ivan Rungger, Stefano Sanvito, and Shimin Hou
Phys. Rev. B 94, 035411 – Published 8 July 2016
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Abstract

We explain how the electrical current flow in a molecular junction can modify the vibrational spectrum of the molecule by renormalizing its normal modes of oscillations. This is demonstrated with first-principles self-consistent transport theory, where the current-induced forces are evaluated from the expectation value of the ionic momentum operator. We explore here the case of H2 sandwiched between two Au electrodes and show that the current produces stiffening of the transverse translational and rotational modes and softening of the stretching modes along the current direction. Such behavior is understood in terms of charge redistribution, potential drop, and elasticity changes as a function of the current.

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  • Received 14 March 2016
  • Revised 17 June 2016

DOI:https://doi.org/10.1103/PhysRevB.94.035411

©2016 American Physical Society

Physics Subject Headings (PhySH)

  1. Research Areas
  1. Physical Systems
Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Meilin Bai1,2, Clotilde S. Cucinotta2,*, Zhuoling Jiang1, Hao Wang1, Yongfeng Wang1,3, Ivan Rungger2,4, Stefano Sanvito2,*, and Shimin Hou1,3,*

  • 1Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China
  • 2School of Physics, Advanced Materials and Bioengineering Research Centre (AMBER) and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) Institute, Trinity College, Dublin 2, Ireland
  • 3Beida Information Research (BIR), Tianjin 300457, China
  • 4Materials Division, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom

  • *Corresponding authors: cucinotc@tcd.ie; SANVITOS@tcd.ie; smhou@pku.edu.cn

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Issue

Vol. 94, Iss. 3 — 15 July 2016

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