Microscopic study of electrical transport through individual molecules with metallic contacts: I. 'Band' lineup, voltage drop and high-field transport

摘要

We present the first in a series of microscopic studies of electricaltransport through individual molecules with metallic contacts. We view themolecules as ``heterostructures'' composed of chemically well-defined atomicgroups, and analyze the device characteristics in terms of the charge andpotential response of these atomic-groups to the perturbation induced by themetal-molecule coupling and the applied electrical field, which are modeledusing a first-principles based self-consistent matrix Green's function (SCMGF)method. As the first example, we examine the devices formed by attaching twobenzene-based molecular radicals--phenyl dithiol (PDT) and biphenyl dithiol(BPD)--symmetrically onto two semi-infinite gold electrodes through the endsulfur atoms.