  We use our recently proposed accelerated dynamics algorithm (Tiwary & van de
Walle, 2011) to calculate temperature and stress dependence of activation free
energy for surface nucleation of dislocations in pristine Gold nanopillars
under realistic loads. While maintaining fully atomistic resolution, we achieve
the fraction of a second time-scale regime. We find that the activation free
energy depends significantly on the driving force (stress or strain) and
temperature, leading to very high activation entropies. We also perform
compression tests on Gold nanopillars for strain rates varying between 7 orders
of magnitudes, reaching as low as 10^3/s. Our calculations show the
quantitative effects on the yield point of unrealistic strain-rate Molecular
Dynamics calculations: we find that while the failure mechanism for <001>
compression of Gold nanopillars remains the same across the entire strain-rate
range, the elastic limit (defined as stress for nucleation of the first
dislocation) depends significantly on the strain-rate. We also propose a new
methodology that overcomes some of the limits in our original accelerated
dynamics scheme (and accelerated dynamics methods in general). We lay out our
methods in sufficient details so as to be used for understanding and predicting
deformation mechanism under realistic driving forces for various problems.
