Tecnologico de Monterrey

Abstract：

Artificial Colloidal Ice is a model system for geometric frustration,which has the advantage that its dynamics are accessible on experimental time and length scales. It consists of magnetic colloids placed inside bistable potentials,realized by lithographically etching grooves into a substrate. The superparamagnetic colloids can be made to interact by applying an external magnetic field,usually perpendicular to the surface,which makes them repulsive.

Using numerical simulations, we find that if the rotational symmetryof the interactions is broken by tilting the field, the system presents many interesting phenomena. When quenching at finite times, the particles freeze in disordered configurations, even in the absence of quenched disorder in the underlying substrate. On the other hand, when starting from an ordered state with repulsiveinteractions, the rotation of the field induces a diffusionless, martensite-like transformation, which interestingly, falls into ordered states only at fast transition rates, but becomes disordered if the transition is carried out slowly enough.

Brief CV of Dr. Antonio Ortiz-Ambriz：

Antonio Ortiz-Ambriz did his Ph. D. in optics at Tecnológico de Monterrey,where he specialized in optical tweezers. He then went to work as a postdoctoral researcher at the University of Barcelona with Prof. Pietro Tierno. During this time,he worked in colloidal model systems of non-equilibrium statistical physics,combining magnetic colloids,optical tweezers,microlithography,and numerical simulations. Currently,he is a research professor in the science department at Tecnologico de Monterrey.

报告地点：M楼253会议室

主持人：Erdal C. Oguz 副研究员

联系人：傅琦 （82649469）