Investigation of Exciton-exciton and Biexcitonic Interactions in Nanomaterials using Explicitly- correlated Quasiparticle Kernel Method

Syracuse University, Syracuse NY

Investigators

Abstract

With support from the Chemical Theory, Models and Computational Methods (CTMC) Program in the Division of Chemistry, Arindam Chakraborty of Syracuse University will investigate a specific class of quantum molecular interactions in nanomaterials, specifically exciton-exciton and bi-excitonic states. Using a new methodology to reduce the computational costs for charactering these interactions, Dr. Chakraborty and his group will study the fundamental processes governing these light-matter interactions as well as the resulting excited states generated in nanomaterials. These exotic excited states are known frontrunners for critically important technological advances in areas such as solar energy conversion and storage, quantum computing and quantum information processing, and the development of high-speed nano-electronics, and of ultra-small bright light sources such as nano-lasers. Realization of the full potential of these nanomaterials requires the ability to judiciously control the shape, size, and chemical functionalization of nanoparticles in order to achieve desired, precise chemical and physical properties appropriate for these applications. The first principle-based quantum chemical calculations that Chakraborty and his team are conducting are aimed at reaching this level of predictive power and control. These research activities will foster workforce development in science, technology, engineering and mathematics (STEM) and in the training of undergraduate and graduate students in cloud-based scientific computing, curation and management of large-scale data, and in the computer-assisted discovery of novel nanomaterials. The real-space explicitly-correlated quasiparticle kernel approach currently being developed in the Chakraborty group aims to addresse the prohibitively high computational effort associated with the study of large nanoparticles. Specifically, ground electronic structure calculations will be performed using atom-centered pseudo-potentials and electronically excited states will be described utilizing a quasi-particle representation with an effective electron-hole Hamiltonian. Many-body quantum mechanical correlation effects are included in the calculations by employing a real-space formalism and using an explicitly correlated frequency-dependent electron-hole interaction kernel operator. The method developed is being used to answer questions about coupling between bright and dark excitonic states, as well as effects of shape anisotropy, size distribution, lifetime of excited states, and temperature of bi-exciton stability. The findings of these computational studies will likely inform the design and enable the discovery of novel materials and help to chart the course for follow-on exploratory research in the field. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.