Sliding Charge-Density Waves

Finite--Size Fluctuations in Sliding Charge--Density Waves: Rob Thorne's Skepticism Is Vindicated. (Myers; 63, 64)

Chris Myers wanted a thesis project involving dynamical systems, so I suggested thinking about the dynamics of charge--density waves. We gradually got sucked into using the methods of critical phenomena and scaling, despite Rob Thorne's assertion that the experiments purportedly seeing scaling were wrong. He said that every sample he looked at looked completely different, and that the experiments published were those that looked only at one sample. Myers did a marvelous job of finding new algorithms for locating the transition, finding new implementations that accelerating the dynamics, developing graphical displays and command--line interfaces for exploring the parameter space, finding scaling methods and extracting exponents.

A picture of the sliding of a CDW by one wavelength, right at depinning. The first point to move is marked in blue: the last is red. The animation (using DynamicLattice) is one of the demos available for LASSPTOOLS.

In the end, we found a new finite--size scaling region, in which every sample looks completely different. Matching our system size to Thorne and Brock's new measurements of the correlation length, our simulations now looked strikingly similar to data taken straight from Thorne's thesis.

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Sethna's Research 90-94
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Last modified: February 8, 1995

James P. Sethna,

Statistical Mechanics: Entropy, Order Parameters, and Complexity, now available at Oxford University Press (USA, Europe).