Charge transfer versus molecular conductance: molecular orbital symmetry turns quantum interference rules upside down

Abstract

Molecular orbital symmetry considerations can strongly affect the nature of quantum interference effects in charge transfer..

Quantum interference effects in biphenyl dithiol for gas detection

“…These are shown in Figure 2a, left panel; the arrows point the direction of net current flow from the left to the right electrode. E −E F = −1.00 eV, constructively interact, which are consistent with those previous results 43 . The antiresonance can be characterized by the reversal of ring currents 58 .…”

“…In the case of NH 3 , the sharp dip in T (E) appears at ∼ -1.21 eV below the Fermi energy indicating antiresonance. For BPDT without gas adsorption, a previous study 43 has demonstrated that large transmission near the Fermi energy results from constructive contributions from HOMO and LUMO. These are shown in Figure 2a, left panel; the arrows point the direction of net current flow from the left to the right electrode.…”

“…A few theoretical studies 37,38,41,42 based on a combination of the nonequilibrium Green's function (NEGF) technique and density functional theory (DFT) were carried out to investigate the electronic structure and transport properties of BPDT. At least one DFTbased study 43 has demonstrated quantum interference effects in Au-S-BPDT-S-Au junctions, resulting from different molecular bridge sites between the BPDT and electrodes. At least one DFTbased study 43 has demonstrated quantum interference effects in Au-S-BPDT-S-Au junctions, resulting from different molecular bridge sites between the BPDT and electrodes.…”

Characterizing destructive quantum interference in electron transport

“…Destructive quantum interference (DQI) is one notable exception to this principle. Some molecules (such as benzene) have multiple paths [6,7] for transporting electrons across the junction, and these paths may destructively interfere with each other to suppress or even block current [8][9][10][11]. From an applications perspective, DQI may result in good molecular insulators [3].…”

Interfering with interference

“…The link between these related fields can be seen in the general assumption that the electron transport/transfer properties of a bridging molecule will be preserved when moving from system to system. However, writing in Chemical Science, Ferdinand Grozema and colleagues 1 have now shown that this assumption can be very misleading, and that electronic properties can be very different depending on how exactly the molecule is 'wired up' .…”