Geometry of slow structural fluctuations in a supercooled binary alloy

Phys Rev Lett. 2010 Mar 12;104(10):105701. doi: 10.1103/PhysRevLett.104.105701. Epub 2010 Mar 9.


The liquid structure of a glass-forming binary alloy is studied using molecular dynamics simulations. The analysis employs the geometrical approach of Frank and Kasper to establish that the supercooled liquid contains extended clusters characterized by the same short range order as the crystal. The steep increase in the heat capacity on cooling is directly coupled to the growing fluctuations of the Frank-Kasper clusters. The relaxation of particles in the clusters dominates the slow tail of the self-intermediate scattering function.