Collaborative Research: Multi-configurational Methods for Charge Transport in Nanoscale Electronics

Butler University, Indianapolis IN

Investigators

Abstract

Professors Erik Hoy of Rowan University and Andrew Sand of Butler University are supported by an award from the Chemical Theory, Models and Computational Methods (CTMC) program in the Division of Chemistry to characterize novel charge transport processes at the quantum level. Understanding charge transport is vital to pursuing new developments in areas considered critically important to long-term national economic success including electronics, solar energy, and materials development. Nanoscale organic electronic devices display unique charge transport properties that can be used to design improved electronic devices (ex. transistors, resistors), but it is challenging to describe charge transport in many of these devices using existing computational methods. The joint Rowan and Butler team will develop new computational tools for generating the charge transport data needed to design the next generation of electronic devices based on non-classical charge transport effects. The developed computational tools will be incorporated into the OpenMolcas software package, which is widely used in both educational and research efforts. Both Butler University and Rowan University have strong commitments to undergraduate education, and a core educational outcome of this project is the development of computationally-engaged undergraduate students fit for either academic or industry positions. Through student recruitment partnerships with mentorship programs and local community colleges, this project provides a pathway into research for students from non-traditional backgrounds and underrepresented groups in the computational sciences. Nanoscale organic electronic devices that operate at the single-molecule level are a key experimental platform for enhancing the scientific community’s understanding of charge transport at the quantum level. Created by combining single organic molecules with metal or carbon-based electrodes, single-molecule devices hold the potential to be the foundation for the next generation of transistors, resistors, and switches for nanoscale electronics. Large gaps remain in our theoretical understanding of non-classical charge transport effects in nanoscale electronics such as the reversal of the expected electrical conductance decay with increasing molecular length. A key reason for this is the limited treatment of electron-electron interactions (electron correlation) by existing transport methods particularly strong/multireference correlation. To resolve this, the Hoy/Sand research team will develop a fully-quantum family of multiconfigurational charge transport methods based on multiconfiguration pair density functional theory (MC-PDFT) combined with the non-equilibrium Green’s function formalism (NEGF). Key objectives include the development of new MC-PDFT-based effective Hamiltonians and self-consistent optimization schemes for multiconfigurational Green’s function transport theories. The integration of these developments within an open-source modular Python framework allows for the characterization of multireference correlation effects in quantum transport phenomena. Using these NEGF-MCPDFT methodologies, the team will investigate including reversed conductance decay, Coulomb blockades, and Kondo Resonances to enhance the scientific community’s understanding of quantum charge transport phenomena. 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.