Figure 3
Current going through the interference-based molecular switch.
The HOMO-LUMO gap of the centre group is Δgap = 1 eV. Each side-group state is capacitively coupled with the corresponding contact with the lever arm 0.2. When the basis voltage Vsd = 0, states A and D have an energy difference δ = 0.01 eV, which vanishes at Vsd = 0.05 V. The basis voltage is antisymmetrically applied to the molecule, i.e. μL = eVsd/2 and μR = −eVsd/2. If the basis voltage is not antisymmetrically applied, i.e. the voltage is only applied on one side and the other side is grounded, the current map will be tilted rather than symmetric about a vertical line, however the destructive interference would still be achieved. The tunnelling coupling between four localised states is J = 0.1 eV and the coupling between side groups and contacts is γ = 1 meV. The temperature is 300 K. We have assumed that ΔB = ΔC when the gate voltage Vg = 0, i.e. the gate voltage of maximum interference is Vc = 0. See Methods for details of the model and how we choose parameters.
