Fri, Oct 05, 2012 @ 02:00 PM - 03:00 PM
Ming Hsieh Department of Electrical Engineering
Conferences, Lectures, & Seminars
Speaker: R. Stanley Williams, Hewlett-Packard Labs
Talk Title: Mott Memristors, Spiking Neuristors and Touring Complete Computing with an Electronic Action Potential
Abstract: Dr. Matthew Pickett and I have been collaborating on a project at HP Labs to explore the possibility of using “locally-active memristors” as the basis
for extremely low-power transistorless computation. We first analyzed the thermally-induced first order phase transition from a Mott insulator to
a highly conducting state in a family of correlated-electron transition-metal oxides, such as Ti4O7 and NbO2. The current-voltage characteristic
of a simple cross-point device that has a thin film of such an oxide sandwiched between two metal electrodes displays a current-controlled
or ‘S’-type negative differential resistance (NDR) caused by Joule self-heating if the ambient temperature is below the metal-insulator transition
(MIT). We derived simple analytical equations for the behavior these devices [1,2] that quantitatively reproduce their experimentally measured
electrical characteristics with only one or two fitting parameters, and found that the resulting dynamical model was mathematically equivalent to
the “memristive system” formulation of Leon Chua and Steve Kang ; we thus call these devices “Mott Memristors”. Moreover, these devices
display the property of “local activity”; because of the NDR, they are capable of injecting energy into a circuit (converting DC to AC electrical power)
over a limited biasing range. We built and demonstrated Pearson-Anson oscillators based on a parallel circuit of one Mott memristor and one
capacitor, and were able to quantitatively model the dynamical behavior of the circuit, including the subnanosecond and subpicoJoule memristor
switching time and energy, using SPICE. We then built a neuristor, an active subcircuit originally proposed by Hewitt Crane  in 1960 without
an experimental implementation, using two Mott memristors and two capacitors. The neuristor electronically emulates the Hodgkin-Huxley model
of the axon action potential of a neuron, which has been recently shown by Chua et al.  to be a circuit with two parallel memristors, and we
show experimental results that are quantitatively matched by SPICE simulations of the output bifurcation, signal gain and spiking behavior that
are believed to be the basis for computation in biological systems. Finally, through SPICE, we demonstrate that spiking neuristors are capable of
Boolean logic and Touring complete computation by designing and simulating the one dimensional cellular nonlinear network based on ‘Rule 137’.
1. Pickett, M. D., Borghetti, J., Yang, J. J., Medeiros-Ribeiro, G. & Williams, R. S. Coexistence of memristance and negative differential resistance in a nanoscale metal-oxide-metal system. Advanced Materials (2011).
2. Pickett, M. D. & Williams, R. S. Sub-100 femtoJoule and sub-nanosecond thermally-driven threshold switching in niobium oxide crosspoint nanodevices. Nanotechnology In Press (2012).
3. Chua, L. & Kang, S. Memristive devices and systems. Proceedings of the IEEE 64, 209-223 (1976).
4. Crane, H. D. The Neuristor. IRE Transactions on Electronic Computers EC-9, 370-371 (1960).
5. Chua, L., Sbitnev, V. & Kim, H. Hodgkin-Huxley axon is made of memristors. International Journal of Bifurcation and Chaos 22, 1-48 (2012).
Biography: R. Stanley Williams is an HP Senior Fellow at Hewlett-Packard Laboratories, one of only five active technologists in HP with this title, and the Director of the Cognitive
Systems Laboratory. He received a B.A. degree in Chemical Physics in 1974 from Rice University and his Ph.D. in Physical Chemistry from U. C. Berkeley in 1978. He was
a Member of Technical Staff at AT&T Bell Labs from 1978-80 and a faculty member (Assistant, Associate and Full Professor) of the Chemistry Department at UCLA from
1980 – 1995. He joined HP Labs in 1995 to found the Quantum Science Research group, which originally focused on fundamental research at the nanometer scale. His
primary scientific research during the past thirty years has been in the areas of solid-state chemistry and physics, and their applications to technology . In 2008, a team
of researchers he led announced that they had built and demonstrated the first intentional memristor, the fourth fundamental electronic circuit element predicted by
Prof. Leon Chua in 1971, complementing the capacitor, resistor and inductor. In 2010, he was named one of the first recipients of the HP CEO’s Award for Innovation
for his work in sensing systems (CeNSE, the Central Nervous System for the Earth). He has received other awards for business, scientific and academic achievement,
including the 2009 EETimes Innovator of the Year ACE Award, the 2007 Glenn T. Seaborg Medal for contributions to Chemistry, the 2004 Herman Bloch Medal for
Industrial Research, and the 2000 Julius Springer Award for Applied Physics. He has over 130 US patents with ~100 pending, more than 200 patents outside the US,
and over 380 papers published in reviewed scientific journals.
Location: Olin Hall of Engineering (OHE) - 132
Audiences: Everyone Is Invited
Posted By: Marilyn Poplawski