8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P8.62Thu 811:10-14:00Phase-separation perspective on dynamicheterogeneities in glass-forming liquidsPaolo Verrocchio, 1 Chiara Cammarota, 2 Andrea Cavagna, 3 Irene Giardina, 3Giacomo Gradenigo, 4 Tomas Grigera, 5 and Giorgio Parisi 41 University of Trento, via sommarive 14, 38100, Trento, Italy2 IPhT CEA, Paris, France3 Istituto Sistemi Complessi ISC-CNR, Rome, Italy4 Department of Physics, University of Rome “La Sapienza”, Roma, Italy5 INIFTA, La Plata, ArgentinaWe study dynamic heterogeneities in a model glass former whose overlap with a referenceconfiguration is constrained to a fixed value. We find that the system phase separates into regionsof small and large overlap, indicating that a nonzero surface tension plays an important role inthe formation of dynamical heterogeneities. We calculate an appropriate thermodynamic potentialand find evidence of a Maxwell construction consistent with a spinodal decomposition of twophases. Our results suggest that even in standard, unconstrained systems dynamic heterogeneitiesare the expression of an ephemeral phase-separating regime ruled by a finite surface tension[1]. Within the framework of the Random First Order Theory of the glass transition, this isof high interest, since interfaces (and surface tension) play a key role in explaining the growthof amorphous order close to the glass transition in terms of nucleation among metastable states [2].[1] C. Cammarota, A. Cavagna, I. Giardina, G. Gradenigo, T. S. Grigera, G. Parisi and P.Verrocchio, Phys. Rev. Lett. 105, 055703 (2010)[2] G. Biroli, J. -P. Bouchaud, A. Cavagna, T. S. Grigera, P. Verrocchio, Nature Physics 4, 771-775(2008)62