Molecular electronics -from structure to circuit dynamics

In this work, we study the dynamics of molecular quantum-dot cellular automata (QCA) devices by combining the technique of quantum chemistry and coherence vector formalism. First, we apply the quantum chemistry ab initio calculation on the single molecule, and construct a simple model Hamiltonian for each QCA cell based on the calculation. For a three-dot molecule discussed in this work, we show a 3×3 Hamiltonian is sufficient to describe its switching behavior. The second step is to use the model Hamiltonian to calculate the coherence vector evolved as time, from which we will investigate the dynamic behavior of various QCA devices and circuits. Finally, we discuss the structure-functionality relation between the molecular structure and circuit dynamics.