Conductance Properties of Stilbenoid Molecules

Abstract

Electronic transport on the molecular scale is a rapidly developing field. Carbon‐based molecular devices are a special class with many potential applications. The graphic shows schematically a stilbene molecule connected via polyene chains of variable length to carbon nanotubes which act as electrodes. Electron transport through this system is theoretically investigated by combining a density‐functional based approach with the Landauer formalism.

Oscillation of Conductance in Molecular Junctions of Carbon Ladder Compounds

“…The conductance oscillation is also obtained from B3PW91/LANL2DZ calculations, as shown in Table . A previous study based on the Landauer formalism predicted conductance oscillation in the molecular wires composed of stilbene (1,2-diphenylethylene) and two alkene chains . Thus, conductance oscillation should occur not only in atomic wires but also in molecular wires in general.…”

Oscillation of Conductance in Molecular Junctions of Carbon Ladder Compounds

“…The conductance oscillation is also obtained from B3PW91/LANL2DZ calculations, as shown in Table . A previous study based on the Landauer formalism predicted conductance oscillation in the molecular wires composed of stilbene (1,2-diphenylethylene) and two alkene chains . Thus, conductance oscillation should occur not only in atomic wires but also in molecular wires in general.…”

Can molecular projected density of states (PDOS) be systematically used in electronic conductance analysis?

“…More specifically, it has become very common to analyze G( ) in terms of the different partial molecular components which enter the full DOS, i.e. the PDOS on the various MOs [33][34][35][36][37] . Since the energy region of interest for the conductance is that one around the Fermi level, one usually takes into account the molecular orbitals around the fundamental gap, e.g.…”

Nanowiring by Molecules

“…Conduction occurs therefore via “hole migration”. To observe conduction by electron migration, one would need to use electrodes with different Fermi energy or to move the energy levels of the bridge by applying a gating voltage. ,− We compute the current using a scattering theory formalism 22 similar to the Landauer approach. ,− ,, It is given by averaging the transmission function over the one-electron states of the electrodes: 20 g (ε μ , V , T ) is the Fermi window 21 that is centered about the Fermi energy, E Fermi , and has a width that equals the applied voltage V with rounded wings due to the finite temperature T . The onset of conduction is a rising exponential function of the applied voltage and occurs when the wings of the Fermi window begin to overlap with the HOMO.…”

“…proach. 18,[23][24][25][26][27][28][29][30][31][32]54,55 It is given by averaging the transmission function over the one-electron states of the electrodes: 20 g( µ ,V,T) is the Fermi window 21 that is centered about the Fermi energy, E Fermi , and has a width that equals the applied voltage V with rounded wings due to the finite temperature T. The onset of conduction is a rising exponential function of the applied voltage and occurs when the wings of the Fermi window begin to overlap with the HOMO. The inset in Figure 4 shows the same curves computed in the approximation where the effect of the voltage is not included in the computation of the MOs.…”

Oscillation of Conductance in Molecular Junctions of Carbon Ladder Compounds

“…The conductance oscillation is also obtained from B3PW91/LANL2DZ calculations, as shown in Table . A previous study based on the Landauer formalism predicted conductance oscillation in the molecular wires composed of stilbene (1,2-diphenylethylene) and two alkene chains . Thus, conductance oscillation should occur not only in atomic wires but also in molecular wires in general.…”

Can molecular projected density of states (PDOS) be systematically used in electronic conductance analysis?

“…More specifically, it has become very common to analyze G( ) in terms of the different partial molecular components which enter the full DOS, i.e. the PDOS on the various MOs [33][34][35][36][37] . Since the energy region of interest for the conductance is that one around the Fermi level, one usually takes into account the molecular orbitals around the fundamental gap, e.g.…”

Nanowiring by Molecules

“…Conduction occurs therefore via “hole migration”. To observe conduction by electron migration, one would need to use electrodes with different Fermi energy or to move the energy levels of the bridge by applying a gating voltage. ,− We compute the current using a scattering theory formalism 22 similar to the Landauer approach. ,− ,, It is given by averaging the transmission function over the one-electron states of the electrodes: 20 g (ε μ , V , T ) is the Fermi window 21 that is centered about the Fermi energy, E Fermi , and has a width that equals the applied voltage V with rounded wings due to the finite temperature T . The onset of conduction is a rising exponential function of the applied voltage and occurs when the wings of the Fermi window begin to overlap with the HOMO.…”

“…proach. 18,[23][24][25][26][27][28][29][30][31][32]54,55 It is given by averaging the transmission function over the one-electron states of the electrodes: 20 g( µ ,V,T) is the Fermi window 21 that is centered about the Fermi energy, E Fermi , and has a width that equals the applied voltage V with rounded wings due to the finite temperature T. The onset of conduction is a rising exponential function of the applied voltage and occurs when the wings of the Fermi window begin to overlap with the HOMO. The inset in Figure 4 shows the same curves computed in the approximation where the effect of the voltage is not included in the computation of the MOs.…”

Oscillation of Conductance in Molecular Junctions of Carbon Ladder Compounds

“…The conductance oscillation is also obtained from B3PW91/LANL2DZ calculations, as shown in Table . A previous study based on the Landauer formalism predicted conductance oscillation in the molecular wires composed of stilbene (1,2-diphenylethylene) and two alkene chains . Thus, conductance oscillation should occur not only in atomic wires but also in molecular wires in general.…”

Can molecular projected density of states (PDOS) be systematically used in electronic conductance analysis?

“…More specifically, it has become very common to analyze G( ) in terms of the different partial molecular components which enter the full DOS, i.e. the PDOS on the various MOs [33][34][35][36][37] . Since the energy region of interest for the conductance is that one around the Fermi level, one usually takes into account the molecular orbitals around the fundamental gap, e.g.…”

Nanowiring by Molecules

“…Conduction occurs therefore via “hole migration”. To observe conduction by electron migration, one would need to use electrodes with different Fermi energy or to move the energy levels of the bridge by applying a gating voltage. ,− We compute the current using a scattering theory formalism 22 similar to the Landauer approach. ,− ,, It is given by averaging the transmission function over the one-electron states of the electrodes: 20 g (ε μ , V , T ) is the Fermi window 21 that is centered about the Fermi energy, E Fermi , and has a width that equals the applied voltage V with rounded wings due to the finite temperature T . The onset of conduction is a rising exponential function of the applied voltage and occurs when the wings of the Fermi window begin to overlap with the HOMO.…”

“…proach. 18,[23][24][25][26][27][28][29][30][31][32]54,55 It is given by averaging the transmission function over the one-electron states of the electrodes: 20 g( µ ,V,T) is the Fermi window 21 that is centered about the Fermi energy, E Fermi , and has a width that equals the applied voltage V with rounded wings due to the finite temperature T. The onset of conduction is a rising exponential function of the applied voltage and occurs when the wings of the Fermi window begin to overlap with the HOMO. The inset in Figure 4 shows the same curves computed in the approximation where the effect of the voltage is not included in the computation of the MOs.…”