The Molecular Foundry - Theory of Nanostructured Materials - Staff

Jeff Neaton

Facility Director, Theory of Nanostructured Materials Facility

Research Interests

My interests center on the electronic structure and transport properties of condensed matter at the nanoscale, particularly interfaces. A broad array of “first-principles” electronic structure theories are drawn upon for this work, most of which are based on density functional theory (DFT), including static methods for ground-state and associated linear-response properties, tight-binding, GW and time-dependent methods for excited-state properties, and steady-state scattering-state approaches to electron transport at finite bias.

Recent Projects

Charge Transport at Nanoscale Interfaces: Single-Molecule Junctions and Beyond
- Mechanically-Controlled Binary Conductance Switching of a Single-Molecule Junction
  Working with the Venkataraman group at Columbia University, we are studying how electrons flow through a molecular junction—a nanometer scale circuit element that contacts gold atoms with a single molecule. Recently, using a combination of theory and experiment, we discovered the electrical resistance through a bipyridine-gold junction can be turned ‘on’ and ‘off’ simply by pushing and pulling the junction. The switching mechanism, which involves mechanical control of the metal-molecule interface geometry and is specific to the pyridine-gold link chemistry, could form the basis of a new class of mechanically-activated single-molecule switches. Learn more
Novel Materials and Mechanisms for Solar Energy Conversion
- Charge Separation via Strain in Silicon Nanowires
  For small-diameter inorganic nanowires, the manner in which sunlight induces charge separation and generates electrical current can differ significantly from mechanisms in bulk solar cells. In this study, we predict axial charge separation in small diameter, partially strained silicon nanowires from ab initio calculations, in collaboration with the Grossman group. We show that this strain-induced effect can be understood from the topologies of near-gap wave functions, and that it is enhanced by quantum confinement. The possibility of utilizing partial strain for charge separation at the nanoscale opens up a new avenue for designing solar cells by morphology control, where effectively a type-II homojunction is formed and charge separation is facilitated by thermalization. Learn more
  
  - Zhigang Wu, J.B. Neaton, and Jeffrey C Grossman
Level Alignment at Nanoscale Interfaces
- Electronic Energy Levels of Weakly Coupled Nanostructures: C₆₀-Metal Interfaces
  There has been considerable recent interest in using organic molecules as components in nanoscale electronic and optoelectronic devices, and thus a critical need has emerged for improved knowledge and control of optical and transport phenomena in organic molecular assemblies, particularly at the metal contact. Optical and transport phenomena at this interface are dictated, in general, by the energetic position of frontier molecular orbitals relative to the metal Fermi energy. A high concentration of such interfaces is expected in organic-based optoelectronic devices, such as bulk heterojunction solar cells base on C₆₀ derivatives. In recent work, based on a parameter-free, electronic structure approach that explicitly accounts for many-electron interactions within the GW approximation, we have developed a physical picture of electronic level alignment at metal-organic interfaces, including recently the C₆₀-metal interface. Learn more
  
  - Jay D. Sau, J. B. Neaton, Hyoung Joon Choi, Steven G. Louie, and Marvin L. Cohen

Selected Publications

A. T. Zayak, H. Choo, Y. S. Hu, D. J. Gargas, S .Cabrini, J. Bokor, P. J. Schuck, and J. B. Neaton "Harnessing Chemical Raman Enhancement for Understanding Organic Adsorbate Binding on Metal Surfaces", J. Phys. Chem. Lett 3, 1357 (2012). Abstract
R. Poloni, B. Smit, and J. B. Neaton, "CO₂ Capture by Metal-Organic Frameworks with van der Waals Density Functionals," J. Phys. Chem. A, 116, 4957 (2012). Abstract
R. Poloni, B. Smit, and J. B. Neaton, "Ligand-Assisted Enhancement of CO₂ Capture in Metal–Organic Frameworks," J. Am. Chem. Soc. 134, 6714 (2012). Abstract
S. Yang, D. Prendergast, and J. B. Neaton, "Tuning Semiconductor Band Edge Energies for Solar Photocatalysis via Surface Ligand Passivation," Nano Lett. 12, 383–388 (2012). Abstract
S. Sharifzadeh, A. Biller, L. Kronik, and J. B. Neaton, "Quasiparticle and Optical Spectroscopy of the Organic Semiconductors Pentacene and PTCDA from First Principles," Phys. Rev. B 85, 125307 (2012). Abstract

Education

2000 Ph.D., Physics, Cornell University

1995 B.S., Summa Cum Laude, Physics, University of Minnesota

Previous Positions

2003-2005 Postdoctoral Fellow, The Molecular Foundry

LBNL Visiting Scholar, Department of Physics, UC – Berkeley 2000-2003

Postdoctoral Fellow, Department of Physics, Rutgers University

Links

Neaton Group

Helios

Scientific Cluster Support at LBNL