  Using Monte Carlo simulations, we investigate the structural characteristics
of an interacting hard sphere system with shifted charge to elucidate the
effect of the non-centrosymmetric interaction on its phase behavior. Two
different phase transitions are identified for this model system. Upon
increasing the volume fraction, an abrupt liquid-to-crystal transition first
occurs at a significantly lower volume fraction in comparison to that of the
centro-charged system. This is due to the stronger effective inter-particle
repulsion caused by the additional charge anisotropy. Moreover, within the
crystal state at higher volume fraction, the system further undergoes a
continuous disorder-to-order transition with respect to the charge orientation.
Detailed analyses in this work disclose the nature of these transitions, and
orientation fluctuation may cause non-centrosymmetric unit cells. The
dependence of crystal formation and orientational ordering on temperature was
also examined. These findings indicate that the non-centrosymmetric interaction
in this work results in additional freedoms to fine-tune the phase diagram and
increase the functionalities of materials. Moreover, these model studies are
essential to advance our future understanding regarding the fundamental
physiochemical properties of novel Janus colloidal particles and protein
crystallization conditions.
