Abstract
We describe a first-principles method for calculating electronic structure, vibrational modes and frequencies,
electron-phonon couplings, and inelastic electron transport properties of an atomic-scale device bridging two
metallic contacts under nonequilibrium conditions. The method extends the density-functional codes SIESTA
and TRANSIESTA that use atomic basis sets. The inelastic conductance characteristics are calculated using the
nonequilibrium Green’s function formalism, and the electron-phonon interaction is addressed with perturbation
theory up to the level of the self-consistent Born approximation. While these calculations often are computationally demanding, we show how they can be approximated by a simple and efficient lowest order expansion.
Our method also addresses effects of energy dissipation and local heating of the junction via detailed calculations
of the power flow. We demonstrate the developed procedures by considering inelastic transport through atomic gold wires of various lengths, thereby extending the results presented in Frederiksen et al. Phys. Rev. Lett. 93, 256601 2004. To illustrate that the method applies more generally to molecular devices, we also calculate the inelastic current through different hydrocarbon molecules between gold electrodes. Both for the wires and the molecules our theory is in quantitative agreement with experiments, and characterizes the system-specific mode selectivity and local heating.
Original language | English |
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Journal | Physical Review B Condensed Matter |
Volume | 75 |
Issue number | 20 |
Pages (from-to) | 205413 |
ISSN | 0163-1829 |
DOIs | |
Publication status | Published - 2007 |
Bibliographical note
Copyright 2007 American Physical SocietyKeywords
- METAL-SURFACES
- MANIPULATION
- MONATOMIC GOLD WIRES
- SCATTERING
- MOLECULAR JUNCTIONS
- ATOMIC-SCALE CONDUCTORS
- SIMULATION
- PHONON INTERACTION
- ELECTRON-TUNNELING SPECTROSCOPY
- MECHANISMS