Electron transport through nanoscale systems such as molecular junctions in the presence of coherent light is a fundamental subject in chemical physics and nanotechnology. In this talk, first, I would like to give a brief overview of quantum transport and introduce several key concepts in electron transport in a time-periodic (ac) field including photon-assisted tunneling and coherent destruction of tunneling. To explore light-driven electron transport through molecules and quantum dots, Meir-Wingree-type formula is derived in the framework of single-particle Green’s functions together with non-HermitianFloquet theory. In a two terminal system, we investigate electron transport through aromatic hydrocarbon in a linearly polarized laser field and propose a new type of optoelectronic switch based on photon-assisted tunneling and destructive quantum interference. Moreover, several new concepts including "current-laser frequency characteristics", "current-field amplitude characteristics", and "current-polarization angle characteristics" are introduced in this talk. In a three-terminal system, a single-molecule optoelectronic router can be built by manipulating the direction of a linearly polarized laser field. In a cross-conjugated system, molecules with odd and even numbers of alkenyl groups exhibit completely different current-polarization characteristics.If time permits, I will talk about my recent progress in photo-induced Coulomb blockade and current fluctuation induced by molecular vibrations.
Liang-Yan Hsuis an assistant research fellow (faculty) of Institute of Atomic and Molecular Sciences of Academia Sinica. He received his Ph.D. from Department of Chemistry, Princeton University in 2015. After doing postdoctoral research at Princeton University and at NorthWesternUniversity, he moved to Taipei and joined the faculty of Academia Sinica in 2017. His research interests include nanoelectronics (molecular electronics and 2D material electronics), methodology of quantum transport theory at the nanoscale, light-matter interactions at the nanoscale (plasmon-coupled exciton transfer and nonlinear spectroscopy), and high-order harmonic generation and ultrafast dynamics. Liang-Yan Hsu has published many important papers in high impact journals such as JACS, Nano Lett., JPC Letters, etc.