Ab Initio Theories of Charge Transport and Energy Conversion at the Nanoscale

Oct 22, 2014  |  4:00pm | ESB 1001
Jeffrey Neaton
Professor of Physics, UC Berkeley
Abstract

The ability to guide the development of complex materials for energy applications at multiple length and time scales hinges on a basic understanding of the physical principles  – or “design rules” – connecting their bulk properties to detailed information about their chemical composition, structure, dimensionality, and environment at the nanoscale. In recent years, ab initio computational approaches, based on density functional theory (DFT), have demonstrated ability to predict measurable properties of complex materials with good accuracy and chemical specificity without adjustable empirical parameters. Here, I will summarize recent results with new ab initio methods for computing and understanding the transport properties of materials from the bulk to the nanoscale. In particular, I will describe a parameter-free theory of hot carrier phonon-assisted relaxation in bulk semiconductors, with implications for optimal ways to nanostructure materials for extracting energetic electrons and holes. Then, focusing on the smallest length scales where tunneling dominates transport, I will describe an accurate ab initio theory of interfacial level alignment to the conductance, thermopower, and rectification of carbon- and porphyrin-based single-molecule junctions, where new physical insight into energy conversion is obtained by relating, in close collaboration with experiment, measured transport phenomena to junction structure and chemistry.

Biography

Jeffrey B. Neaton is a Professor of Physics at the University of California, Berkeley and Director of the Molecular Foundry, a Department of Energy Nanoscale Science Research Center at Lawrence Berkeley National Laboratory, where he is also a Senior Faculty Scientist. He received his Ph.D. in physics from Cornell University in 2000, working with Neil Ashcroft. After a postdoc at Rutgers University, and after having worked at Lawrence Berkeley National Laboratory as a postdoc and staff scientist at the Molecular Foundry, he joined the UC Berkeley faculty in 2014. Neaton received a Lawrence Berkeley National Laboratory Outstanding Achievement Award in 2007, and the Presidential Early Career Award for Scientists and Engineers in 2009. He is a fellow of the American Physical Society, and presently a Division Associate Editor for Physical Review Letters. Often taking place in close collaboration with experiments, Neaton’s current research emphasizes the development and use of ab initio and analytical methods for the understanding of complex and correlated condensed phases of organic and inorganic solids, nanostructures, and interfaces; electronic excited state phenomena, including quasiparticle and optical excitations; weak interactions in nanoporous materials; and low-dimensional transport behavior, particularly in single-molecule junctions. An important context for his research of late has been renewable energy, where novel materials, excited states, oxides, organics, and interfaces feature prominently.

Event TypeSeminar