TY - JOUR
T1 - Raman scattering from molecular conduction junctions
T2 - Charge transfer mechanism
AU - Oren, Michal
AU - Galperin, Michael
AU - Nitzan, Abraham
PY - 2012/3/26
Y1 - 2012/3/26
N2 - We present a model for the charge transfer contribution to surface-enhanced Raman spectroscopy (SERS) in a molecular junction. The model is a generalization of the equilibrium scheme for SERS of a molecule adsorbed on a metal surface. We extend the same physical consideration to a nonequilibrium situation in a biased molecular junction and to nonzero temperatures. Two approaches are considered and compared: a semiclassical approach appropriate for nonresonance Raman scattering, and a quantum approach based on the nonequilibrium Green's function method. Nonequilibrium effects on this contribution to SERS are demonstrated with numerical examples. It is shown that the semiclassical approach provides an excellent approximation to the full quantum calculation as long as the molecular electronic state is outside the Fermi window, that is, as long as the field-induced charge transfer is small.
AB - We present a model for the charge transfer contribution to surface-enhanced Raman spectroscopy (SERS) in a molecular junction. The model is a generalization of the equilibrium scheme for SERS of a molecule adsorbed on a metal surface. We extend the same physical consideration to a nonequilibrium situation in a biased molecular junction and to nonzero temperatures. Two approaches are considered and compared: a semiclassical approach appropriate for nonresonance Raman scattering, and a quantum approach based on the nonequilibrium Green's function method. Nonequilibrium effects on this contribution to SERS are demonstrated with numerical examples. It is shown that the semiclassical approach provides an excellent approximation to the full quantum calculation as long as the molecular electronic state is outside the Fermi window, that is, as long as the field-induced charge transfer is small.
UR - http://www.scopus.com/inward/record.url?scp=84859085041&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.85.115435
DO - 10.1103/PhysRevB.85.115435
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AN - SCOPUS:84859085041
SN - 1098-0121
VL - 85
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 11
M1 - 115435
ER -