Invited Talks: Transition Metal Oxides - University Blog Service - The ...

The John B. Goodenough Symposium in Materials Science & Engineering –
In Honor of His 90 th Birthday
The University of Texas at Austin, Austin, Texas
October 26-27, 2012
Greening Digital Systems Requires Better Quantum Models
Bob Schubring
Wonder Funding 1680 Vine Street, Suite 325, Los Angeles, CA 90028
office: 323.733.1000 | mobile: 734.320.3435
Email: rschubring@gmail.com
Website: http://www.wonderfunding.com
Abstract Body in Space Below:
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Polarization gradients in compositionally-graded perovskite ferroelectric thin films are known to generate
electrical current by an unexplained mechanism that is not corrosion. Barium strontium titanate thin films
have been engineered by compositional grading to compensate for geometric effects, and function as
commercially nonvolatile random-access memories in microcontrollers. Further advancement requires
elucidation of the mechanism by which the unexplained currents happen. The benefits are potentially
enormous. Conventional RAM requires refresh at every clock cycle of the computer. Ferroelectric RAM
holds data indefinitely without refresh, for periods up to 7 years, and does not degrade mechanically as
does flash memory. If feature sizes are reduced and switching speeds increased to match conventional
RAM, the energy and cooling savings will be vast, because most RAM-cached data is not read every clock
cycle. Markets do not price in the cost advantages of these energy savings, because too little is known
about the anomalous current mechanism and how it may limit switching speeds in alternative memory
materials. To overcome this obstacle will require an advanced quantum-mechanical model that accounts
for the anomalous current. The current may be the effect of polarization-driven quantum tunneling but this
is unproven. Thermoelectric tunneling effects were not measurable by thermometry in graded potassium
tantalate niobate thin films, but new calculations show that the likely temperature differences were within
experimental error of the thermometry study. Thus, a secondary benefit of improved quantum-mechanical
models, is that waste heat may be harvested by resulting ferroelectric RAM devices.