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Memristors

Page history last edited by frogheart@... 12 years, 4 months ago

It started with an announcement from HP Labs in May 2008. Scientists there had experimental proof that memristors, hypothesized by Dr. Leon Chua in 1971, existed.[1]  By June 2008, the HP scientists were announcing that they had successfully engineered control over test devices.[2]

 

In its way, it's a quintessential science story as it developed on two parallel tracks. On the first track, there's something called the 'holy trinity' in electrical engineering. It has to do with integrated circuits and voltage characteristics. The 'holy trinity' are: inductors, resistors and capacitors.[3]

 

On the second track, Dr. Chua, professor at the University of California's (Berkeley) Electrical Engineering and Computer Sciences Department, observed, in 1971, "an unfilled symmetry between fundamental electromagnetic equations relating charge and flux and their corresponding passive circuit elements."[4]

 

In other words, from a mathematical perspective something seemed to be missing. Chua theorized that there was a fourth member of the 'holy trinity', a memory resistor or memristor. No one made the connection between Chua's hypothesis and anomalies in voltage characteristics which had been noted in the literature since the 1950s. 

 

It was R. Stanley Williams's work in molecular electronics at the HP Labs that brought the two tracks together. Williams's colleague, Greg Snider found Chua's 1971 memristor hypothesis when he searched for a theoretical explanation of the bizarre voltage occurrences they were encountering in the lab. He brought the theory to Williams and then, "It was several years of scratching my head and thinking about it," before Williams realized that their molecular devices were really memristors. "It just hit me between the eyes."[5] Williams, Snider and colleagues, Dmitri Strukov and Duncan Stewart went on to prove the existence of Dr. Chua's memristor, a circuit element that, unlike any other member of the 'holy trinity', remembers voltage characteristics.

 

Just months after the experimental proof announcement, another HP Labs team, this time led by Duncan Stewart announced that they'd achieved engineering control of a memristor. They built a switch--a memristor switch--that's 50 nanometres by 50 nanometres (50 billionths of a metre x 50 billionths of a metre). It contained a layer of a chemical most people know as a component of sunscreen or white paint, titanium dioxide. Team member, Jianhua Yang then discovered that manipulating the oxygen atoms in the layer would allow him an unprecedented level of control over the device.[6] (To get an idea about how difficult that would be, under Jump points, click Sticky and fast.)

 

A memristor switch can be operated in either digital or analogue modes. In its digital mode, the memristor's ability to retain information about how much and when current had been flowing has some interesting applications in the short term. A memristor device in its digital state could replace the current solid state memory (Flash) found in computers with less expensive nonvolatile random access memory (RAM). For the user, it means no more rebooting when starting up the computer, every program would be instantly available and much less energy would be consumed.[7]

 

In its analogue mode,  the memristor switch has a unique 'in-between' state where dialing to values such as 0.3 or 1.8 is possible and could allow it to process information the way a brain does. That is, in its analogue state, the memristor could lead to computer hardware that learns. It would allow pattern-matching (only one of a human brain's learning functions), which could be used for facial and voice recognition applications.[8]

 

Jump back

Sticky and fast

 

Jump points

See me, feel me

Footnotes

  1. Jordan, S. (May 5, 2008) True news from H-P--memristor nano-memory element. Carpe Nano. [Online blog posting] (Accessed May 6, 2008, from http://carpenano.blogspot.com/2008/05/true-news-from-h-p-memristor-nano.html)
  2. Beckett, J. (2008) Engineering memristor; control over device could pave way to computers that learn. HP Labs News, June 2008. [Online article] (Accessed June 23, 2008 from http://www.hpl.hp.com/news/2008/apr-jun/engineering_memristor.html)
  3. Adee, S. (2008) The Mysterious Memristor. IEE Spectrum Online, May 2008. [Online article] (Accessed July 3, 2008 from http://www.spectrum.ieee.org/may08/6207)
  4. Jordan, S. (May 5, 2008) True news from H-P--memristor nano-memory element. Carpe Nano. [Online blog posting] (Accessed May 6, 2008, from http://carpenano.blogspot.com/2008/05/true-news-from-h-p-memristor-nano.html)
  5. Adee, S. (2008) The Mysterious Memristor. IEE Spectrum Online, May 2008. [Online article] (Accessed July 3, 2008 from http://www.spectrum.ieee.org/may08/6207)
  6. Beckett, J. (2008) Engineering memristor; control over device could pave way to computers that learn. HP Labs News, June 2008. [Online article] (Accessed June 23, 2008 from http://www.hpl.hp.com/news/2008/apr-jun/engineering_memristor.html)
  7. Beckett, J. (2008) Engineering memristor; control over device could pave way to computers that learn. HP Labs News, June 2008. [Online article] (Accessed June 23, 2008 from http://www.hpl.hp.com/news/2008/apr-jun/engineering_memristor.html)
  8. Beckett, J. (2008) Engineering memristor; control over device could pave way to computers that learn. HP Labs News, June 2008. [Online article] (Accessed June 23, 2008 from http://www.hpl.hp.com/news/2008/apr-jun/engineering_memristor.html)

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