New Paradigms for Materials and Devices: Coherent Single Atom Devices and Intelligent Nanowire Networks
This talk provides an overview of activities within my group related to new materials and devices. First, the potential to create high-fidelity quantum interference devices is demonstrated. Single atoms are used to create electron cavities with large energy separations (>0.25eV) between the eigenstates or modes. The operation of the device is demonstrated by mapping the amplitude and phase of the scattered electrons across the device and the coupling into the leads, including resonant coupling to the electronic states within the cavity. Single atom gating is also presented as are DFT simulations of device operation. The latter part of the talk describes the behaviour of networks comprised of random assemblies of individual wires coated with a resistive layer that controls global conduction. We develop a universal scaling relationship and demonstrate the presence of locally connected regions or cells within the network that ultimately lead to global conduction1. Network connectivity evolves in response to an applied electric field to create materials whose conductivity can be arbitrarily controlled. We demonstrate the generality of these concepts by fabricating and testing memory devices and discuss potential opportunities in the area of neuromorphic computing.  P. N. Nirmalraj et al. “Manipulating Connectivity and Conductivity in Random Nanowire,” Nano Lett 12, 5966-5971 (2012)
Prof. John J. Boland
Trinity College Dublin, Ireland
Prof. John Boland received a BSc degree in chemistry from University College Dublin and a PhD in chemical physics from the California Institute of Technology. From 1984 to 1994 he was a member of the research staff at the IBM T.J. Watson Research Center. He was appointed in 1994 the J.J. Hermans Chair Professor of Chemistry and Applied and Materials Science at the University of North Carolina at Chapel Hill. In 2002 Prof. Boland moved to the School of Chemistry at Trinity College Dublin and served as the Director of the CRANN Nanoscience Institute from 2005 to 2013. He is an expert on surface chemistry, the mechanical and electrical properties of nanowires and networks, and the use STM/AFM to elucidate nanoscale materials and device properties. He is fellow of Trinity College (2008), a fellow of the American Vacuum Society (2009) and a fellow of the American Association for the Advancement of Science (2010). He was the Laureate of the 11th ACSIN Nanoscience Prize (2011) and was recently awarded a prestigious ERC Advanced Grant (2013).