Nucleation is absent in the equilibration of supercooled liquids below T_MCT

According to random first-order transition (RFOT) theory, supercooled liquids cooled below the mode-coupling temperature T_MCT exhibit a transition to a state in which deep energy landscape minima are ubiquitous, but transitions between them are slow [1]. Nucleation has been suggested to play a key role in the sub-T_MCT dynamics of these systems, with structural evolution proceeding via the size-limited nucleation of droplets of "aperiodic crystal" [2] within domains of different, incompatible states [3,4]. In this talk, we present direct evidence from molecular dynamics simulations that nucleation is absent from the equilibration dynamics of supercooled liquids below T_MCT. The structural evolution, characterized by softness [5], is instead remarkably local. We find that softness sensitively captures the evolution of local structure on long time scales while remaining insensitive to large but mostly-reversible changes in the inherent state on short time scales.

 

[1] G. Biroli and J.-P. Bouchaud, in Structural Glasses and Supercooled Liquids: Theory, Experiment, and Applications edited by P. G. Wolynes and V. Lubchenkos (Wiley, New York, 2012), pp. 31–113.

[2] T. R. Kirkpatrick, D. Thirumalai, and P. G. Wolynes, Phys. Rev. A 40, 1045 (1989).

[3] M. Dzero, J. Schmalian, and P. G. Wolynes, Phys. Rev. B 72, 100201 (2005).

[4] G. Biroli, C. Cammarota, G. Tarjus, and M. Tarzia, Phys. Rev. B 98, 174206 (2018).

[5] S. S. Schoenholz, E. D. Cubuk, D. M. Sussman1, E. Kaxiras and A. J. Liu, Nat. Phys. 12, 469 (2016).