Optical Control of Transport and Dynamics in Junctions

Northwestern University, Evanston IL

Investigators

Abstract

Tamar Seideman of Northwestern University is supported by an award from the Theory Models and Computational Method program for developing a new approach to coherent control of both electric transport and vibrational dynamics in molecular junctions. The approach is based on semiconductor molecular electronics and the application of low-frequency, sub-bandgap light. This project focuses on theory and computational realizations of electronic transport in nanodevices and coherent control. The present formalism consistently accounts for the electron scattering dynamics, the possibility of nuclear dynamics, the nonadiabatic coupling of the electronic and vibrational motions, the interaction with light, the plasmonic response of the electrodes, and the dissipation due to electron hole pair excitation and to electrode phonons. Additionally, a novel numerical method is developed for computing the transport properties of molecular junctions. This method is applicable to semiconductor-based junctions and is efficient enough to be implemented in a control scheme. Among the applications to be addressed with theoretical and computational emphases are transport, dynamics, plasmonic response in Au-C60-Au junctions, STM driven surface nanochemistry, and nanoplasmonics. Most of these developments are complementary to forefront research in three collaborative experimental groups. This type of collaboration enhances the education and research experience of students in both theoretical and experimental groups. Broader impacts result from the continued engagement of this group in a variety of outreach and teaching activities, including work within the National Center for Learning and Teaching in the nanosciences (NCLT), the Network for Computational Nanotechnology (NCN), the Summer Research Opportunities Program for minority undergraduate students (SROP), the Research Experience for Undergraduates and for Teachers Programs (REU and RET, respectively); work within a program that uses science to create collaboration and friendship between Israeli and Palestinian students; advising and mentoring in two international student exchange programs; guidance of several undergraduate students; and delivery of lectures about nanotechnology to the elderly and to children. Furthermore, the numerical code is made available to the scientific community and is broadly disseminated.