Coherent and Incoherent Control in Material Systems

Proposed are three studies that combine new directions in control theory of complex systems with a rich education and outreach program and several collaborative projects with di�erent experimental groups. The �rst study builds on the success of previous NSF- supported research, where the PI introduced an approach to coherent control of transport via semiconductor-based molecular-scale electronics as a route to circumventing the di�culties asso- ciated with conventional, metal-based molecular-scale electronics that were noted in the previous experimental literature. The proposed research goes beyond her earlier, fully analytical solution, which was restricted to the 1- and 2-site bridge cases and to Markovian dynamics, by developing a numerical method and applying it to explore memory e�ects and multiple-site dynamics. The second research direction introduces a new approach to understanding transport junc- tions, namely, current-induced Raman spectroscopy. It suggests the potential interest of this observable as a route to enlisting the chemical sensitivity of Raman spectra to accurately char- acterize the structure and chemical composition of molecular-scale junctions, and the transport and current-driven dynamics they exhibit. Also proposed are the development and application of a theory and a corresponding numerical method to determine, within a uniform approach, the transport, current-driven dynamics and Raman spectra �rst for a simple adsorbed diatomic molecule and next for a reduced dimensionality model of rhodamine 6G/silver. This study would serve to guide an experiment to be carried out as the next stage. The third proposed research direction introduces a new control concept, namely, quantum optimal environment engineering. The PI proposes application of the new control avenue to guide and manipulate charge transfer reactions with a view to enhancing the e�ciency of dye- sensitized solar cells. More generally, this research aims to develop and apply a theory and a numerical method to optimize, enhance and control reaction outcomes and pathways using reagents that are less costly than coherent light, hence a potential route to economically viable control. The intellectual merit of the proposed activities derives from the combination of formalism development, numerical method development, and two new ideas, all of which are expected to generate new knowledge. The collaboration of the PI with several experimental groups would give the work further intellectual merit and is expected to bene�t the research experience of students in both experimental and theoretical groups. Broader impact is expected to ensue the continued engagement of the PI in a large variety of outreach and teaching activities, several of which are tied with the proposed research program. New activities are currently planned, as the PI begins to serve as International Outreach Direc- tor of Northwestern's Materials Center. These add to continuation of existing activities such as participation in the Summer Research Opportunities Program for minority undergraduate students (SROP), and the Research Experience for Undergraduates and for Teachers Programs (REU and RET, respectively); formation and direction of two international student exchange pro- grams; collaborative curriculum development with a teacher at a south Chicago college; guidance of numerous undergraduate students and several high school students; and delivery of lectures about nanotechnology to the elderly and to children. Furthermore, the numerical code that wil