e-Workshop: All-Spin Logic

Larkhoon Leem tryon16 at stanford.edu
Tue Mar 30 03:11:13 PDT 2010


You are invited to participate:

All-Spin Logic

to be presented by Supriyo Datta, Behtash Behin-Aein and Kaushik Roy from the
Purdue University

on Tuesday, March 30th at 1pm. Stanford site for this tele-seminar
will be set up at Allen (CISX) 316X.


Abstract: The possible use of spin rather than charge as a state
variable in devices for processing and storing information has been
widely discussed, because it could allow low-power operation and might
also have applications in quantum computing. However, spin-based
experiments and proposals for logic applications typically use spin
only as an internal variable, the terminal quantities for each
individual logic gate still being charge-based. This requires repeated
spin-to-charge conversion, using extra hardware that offsets any
possible advantage.

We propose a spintronic device that uses spin at every stage of its
operation: information manipulation, transport, storage, input and
output are all accomplished with magnets and spin-coherent channels.
Contrary to the typical spin/magnet based logic schemes, the all-spin
scheme neither relies on ordinary magnetic fields (generated by
current carrying wires) nor does it rely on electrical read-out of
magnetic states. Binary data are represented by the bi-stable states
of nanomagnets (i.e. magnetic polarization) which can be non-volatile.
Application of a voltage signal to a magnetic contact (input data bit)
creates a spin-current in a channel which can be conveniently guided
and routed to another magnetic contact (output data bit) where it
determines its final state based on spin-torque phenomenon.

The all-spin device could potentially find use for low-power digital
logic since it should satisfy the five essential requirements for
logic applications namely nonlinearity, gain, concatenability,
feedback prevention and a complete set of Boolean operations.
Satisfaction of these essential characteristics paves the way for the
design of large scale digital circuits. Cascading and clocking of
logic gates will be discussed along with the
device/circuit/architecture co-optimization of all-spin logic (ASL).

While the focus of the talk will be on digital logic, it is
interesting to note that the all-spin scheme could provide a basis for
unconventional approaches. For example the spin accumulation in a
channel underneath a magnetic contact could provide a 'weighted
average' of different inputs that makes it switch ("fire") when it
exceeds a threshold like neural networks. Alternatively the magnetic
contacts on top of the channel could possibly serve as Input-Output
interface for spin-based quantum computing.



Biographies of Presenters:

Supriyo Datta received his B.Tech. from the IIT, Kharagpur in 1975,
his Ph.D from the University of Illinois, Urbana-Champaign in 1979 and
joined Purdue University in 1981. The approach pioneered by his group
for the description of quantum transport far from equilibrium has been
widely adopted in the field of nanoelectronics and he shared the IEEE
Cledo Brunetti award in 2002 with his colleague Mark Lundstrom. His
work has also influenced course and curriculum development in
nanoelectronics for which he received the IEEE Leon Kirchmayer award
for Graduate Teaching in 2008. URL:
http://cobweb.ecn.purdue.edu/~datta/

Behtash Behin-Aein received his B.Sc. in electrical engineering from
Purdue University, West Lafayette, IN in 2004. He is currently a
research assistant in Supriyo Datta's research group working towards
his Ph.D at Purdue University. His research interests include spin
devices, spin dynamics in confined magnetic structures, spin transport
and spin-torque phenomenon.

Kaushik Roy received his B.Tech. degree in electronics and electrical
communications engineering from IIT, Kharagpur, India, and Ph.D in
electrical and computer engineering from the University of Illinois at
Urbana- Champaign in 1990. His research interests include VLSI
design/CAD for nano-scale Silicon and non-Silicon technologies,
low-power electronics for portable computing and wireless
communications, VLSI testing and verification, and reconfigurable
computing. Dr. Roy has received the National Science Foundation Career
Development Award in 1995, IBM faculty partnership award, ATT/Lucent
Foundation award, 2005 SRC Technical Excellence Award, SRC Inventors
Award and Purdue College of Engineering Research Excellence Award.
URL: https://engineering.purdue.edu/NRL



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