Submitted Abstract
Current electronic devices (laptops, tablets, smartphones, smartwatches and so on) are built mostly on fundamental principles of “classical” semiconductor physics. Continuous enhancement of their speed and capacity demand new functionality based on explicit quantum-mechanical principles. To this end, it looks promising to employ the geometric phase of quantum states that encodes information about their evolution during various dynamical processes. With respect to the rapidly developing field of molecular electronics, this is related to the molecular Aharonov-Bohm effect (MABE). Recently, it was managed to switch a single electron bipolar conductance via manifestation of the MABE for Zn-etioporphyrin radical anion [J. Lee et al., ACS Nano 8, 6382 (2014)] which provides a prototype of a new electronic device for molecular electronics. This and other recent experiments provide strong motivation for fundamental development of theoretical methods for understanding and controlling the molecular geometric phase to enable its use in potential future technologies. The exploitation of the MABE in novel functional materials requires consideration of large molecules, such as Zn-etioporphyrin and fullerenes. This requires development of new methodologies for modeling the MABE based on the Feynman path-integral formulation of quantum mechanics.Within the PINTA project a reliable methodology for application of the path-integral approach to the MABE will be developed. First of all, this needs derivation of the corresponding propagator for the Feynman integrals involving the geometric vector potential which arises in the Hamiltonian of nuclei treated quantum mechanically. This will be done taking spin-orbit interaction into account, which should be important for future studies and predictions of functional materials for molecular spintronics. The algorithms for an efficient evaluation of the obtained integrals will be designed at the next step. The developed formalism will be implemented eventually in a software code available for other researchers as well. Finally, an application of this code for exploration of the MABE on various models for molecular systems will provide a new insight into this phenomenon. A successful implementation of this project will also pave the way towards explicit first-principles descriptions of the MABE in molecular systems of relevant size and complexity.