  Charge ordering (CO) is a phenomenon in which electrons in solids crystallize
into a periodic pattern of charge-rich and charge-poor sites owing to strong
electron correlations. This usually results in long-range order. In
geometrically frustrated systems, however, a glassy electronic state without
long-range CO has been observed. We found that a charge-ordered organic
material with an isosceles triangular lattice shows charge dynamics associated
with crystallization and vitrification of electrons, which can be understood in
the context of an energy landscape arising from the degeneracy of various CO
patterns. The dynamics suggest that the same nucleation and growth processes
that characterize conventional glass-forming liquids guide the crystallization
of electrons. These similarities may provide insight into our understanding of
the liquid-glass transition.
