Zhai Qiang, Deng Hai-Yao, Gao Xin-Yuan, Lam Leo S I, Yang Sen, Yan Ke, Lam Chi-Hang
MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3AA, Wales.
J Chem Phys. 2025 Jun 21;162(23). doi: 10.1063/5.0271966.
A free surface induces enhanced dynamics in glass formers. We study the dynamical enhancement of glassy films with a distinguishable-particle lattice model of glass free of elastic effects. We demonstrate that the thickness of the surface mobile layer depends on temperature differently under different definitions, although all are based on local structure relaxation rate. The rate can be fitted to a double exponential form with an exponential-of-power-law tail. Our approach and results exclude elasticity as the unique mechanism for the tail. Layer-resolved particle hopping rate, potentially a key measure for activated hopping, is also studied but it exhibits much shallower surface effects.
