Local pathways in coherent electron transport through iron porphyrin complexes: a challenge for first-principles transport calculations

TY - JOUR

T1 - Local pathways in coherent electron transport through iron porphyrin complexes

T2 - a challenge for first-principles transport calculations

AU - Herrmann, Carmen

AU - Solomon, Gemma C.

AU - Ratner, Mark A.

PY - 2010/12/9

Y1 - 2010/12/9

N2 - We investigate the coherent electron transport properties of a selection of iron porphyrin complexes in their low-spin and high-spin states, binding the system to metallic electrodes with three different substitution patterns. We use a study of the local transmission through the complexes and their molecular orbitals to show the role of the various components of the molecular structure in mediating electron transport. While there are energies where the metal center and the axial ligands participate in transport, in the off-resonant energy range, these components simply form a scaffold, and the transport is dominated by transmission through the porphyrin macrocyle alone. This is still true when going from the low-spin to the high-spin state, except that now, an additional iron-centered MO contributes to transport in the formerly off-resonant region. It is found that while the choice of the exchange-correlation functional can strongly influence the quantitative results, our qualitative conclusions hold irrespective of the functional employed.

AB - We investigate the coherent electron transport properties of a selection of iron porphyrin complexes in their low-spin and high-spin states, binding the system to metallic electrodes with three different substitution patterns. We use a study of the local transmission through the complexes and their molecular orbitals to show the role of the various components of the molecular structure in mediating electron transport. While there are energies where the metal center and the axial ligands participate in transport, in the off-resonant energy range, these components simply form a scaffold, and the transport is dominated by transmission through the porphyrin macrocyle alone. This is still true when going from the low-spin to the high-spin state, except that now, an additional iron-centered MO contributes to transport in the formerly off-resonant region. It is found that while the choice of the exchange-correlation functional can strongly influence the quantitative results, our qualitative conclusions hold irrespective of the functional employed.

U2 - 10.1021/jp107147x

DO - 10.1021/jp107147x

M3 - Journal article

SN - 1932-7447

VL - 114

SP - 20813

EP - 20820

JO - The Journal of Physical Chemistry Part C

JF - The Journal of Physical Chemistry Part C

IS - 48

ER -