Anti-coherence based molecular electronics: XOR-gate response

We point out and simulate the possible utility of anti-coherence in molecular electronics. In ballistic transfer through a molecule with a large loop that fulfils a certain phase condition on the loop structure, the transfer would be anti-coherent. By applying one or two control voltages to the molecule, that modify the relative phase through the two parts of the loop, the transfer could be controlled, just like in FET or in XOR gates. The simulations use the absorbing-potential based flux-flux formulae with a Huckel-Hamiltonian in a Landauer formulation, and are numerically equivalent to a weighted time-dependent correlation function. (C) 2002 Elsevier Science B.V. All rights reserved.