AUTHOR=Toledo-Marín J. Quetzalcóatl , Naumis Gerardo G. 

TITLE=Testing Rigidity Transitions in Glass and Crystal Forming Dense Liquids: Viscoelasticity and Dynamical Gaps

JOURNAL=Frontiers in Materials

VOLUME=6

YEAR=2019

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2019.00164

DOI=10.3389/fmats.2019.00164

ISSN=2296-8016

ABSTRACT=<p>A computational study of rigidity for dense fluids of monodisperse and bidisperse hard-disks near a phase and a glass transition respectively is presented. To achieve this goal, the transversal part of the dynamical structure factor is calculated. In both cases, a viscoelastic behavior is obtained, with a dynamical gap determined by a critical wavevector <italic>k</italic><sub><italic>c</italic></sub>. Transversal waves exist for <italic>k</italic> &gt; <italic>k</italic><sub><italic>c</italic></sub> while the maximal correlations happens at frequency ω = 0 for <italic>k</italic> &lt; <italic>k</italic><sub><italic>c</italic></sub>. In both cases <italic>k</italic><sub><italic>c</italic></sub> goes to zero as the freezing point is approached. Both systems are able to fulfill a scaled dynamical law as a power law is found for the critical <italic>k</italic><sub><italic>c</italic></sub> as a function of the packing. The obtained results indicate that this method gives an alternative to study rigidity and constraint theory in dense fluids, since it is possible to assign a number of floppy modes or broken constraints in the liquid by computing the number of modes below <italic>k</italic><sub><italic>c</italic></sub>, as well as an effective average coordination number. Also, this suggests that the critical wavevector <italic>k</italic><sub><italic>c</italic></sub> can serve as a suitable order parameter.</p>