Our research centers on theoretical condensed matter, nanoscience, and renewable energy materials, with particular emphasis on discovery and understanding of complex and correlated organic and inorganic phases and their interfaces; electronic excited states, including quasiparticle and optical excitations; weak (non-covalent) interactions; and low-dimensional transport behavior.
For much of our work, we draw upon contemporary “first-principles” density functional theory (DFT)-based approaches. First-principles approaches are theoretical methods at the nexus of condensed matter physics, quantum chemistry, and computational materials with the ability to predict measurable properties of materials with good accuracy without adjustable empirical parameters, i.e. through approximate solutions of the quantum mechanics of a system of interacting electrons in a field of nuclei.
Our research is often multidisciplinary, focuses on both hard and soft matter, and reflects a breadth consistent with the flexibility of first-principles DFT-based methods. Importantly, we interact closely with experimental research groups to guide and be inspired by state-of-the-art studies of real physical systems, and to validate and further develop our understanding of materials.
Most recently, we have focused on understanding phase behavior, and transport and spectroscopic phenomena, in molecular and organic assemblies; at interfaces between dissimilar materials; and in complex oxides, particularly perovskites. Although structurally distinct, these materials classes share astonishing chemical diversity; highly-localized, sometimes strongly-correlated electronic states; and, in instances, appreciable non-covalent interactions. As such, they present significant challenges to contemporary electronic structure theory. A major theme of our work is to devise analytical and computational methods that exploit connections between these disparate materials classes to create general approximations and methods, design new materials, and understand novel phenomena at the frontiers of physics, chemistry, and materials science.
An important context for our work has been solar energy conversion and carbon emissions mitigation, where excited states, oxides, organics, and interfaces feature prominently. In particular, knowledge of light-matter interactions, charge and neutral excitation energies, current density, and frequency-dependent screening – quantities traditionally difficult to treat with standard DFT-based approaches – is key for understanding assembly, absorption, charge separation, charge dynamics, and chemical reactions.
Our long-term efforts include the development of electronic structure methods to treat increasingly complex materials and study time-dependent phenomena. Linked below are short descriptions of selected present research areas, which lay the groundwork for these goals.