Interface Mobility from Interface Random Walk
Zachary T. Trautt,1,2
Moneesh Upmanyu,1,2*
Alain Karma3
Computational studies aimed at extracting interface mobilities
require driving forces orders of magnitude higher than those
occurring experimentally. We present a computational methodology
that extracts the absolute interface mobility in the zero driving
force limit by monitoring the one-dimensional random walk of
the mean interface position along the interface normal. The
method exploits a fluctuation-dissipation relation similar to
the Stokes-Einstein relation, which relates the diffusion coefficient
of this Brownian-like random walk to the interface mobility.
Atomic-scale simulations of grain boundaries in model crystalline
systems validate the theoretical predictions and highlight the
profound effect of impurities. The generality of this technique,
combined with its inherent spatiotemporal efficiency, should
allow computational studies to effectively complement experiments
in understanding interface kinetics in diverse material systems.
2 Materials Science Program, Colorado School of Mines, Golden, CO 80401, USA.
3 Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA 02115, USA.
* To whom correspondence should be addressed. E-mail: mupmanyu{at}mines.edu
