(74f) FCC-to-BCC Phase Transitions of Convex and Concave Particles

FCC-to-BCC phase is one of the most common solid—solid phase transitions in nature and has been observed in numerous colloidal systems. One great interest is the thermodynamic order of this kind of transitions given that by Landau theory, it can be either first order or second order transition depending on the transformation pathway. In our study, we construct minimal models of hard colloidal particles that could both self assemble into FCC and BCC structures. By varying concavity and particle symmetries, we find that for all our test cases, the FCC-to-BCC phase transition is first order. Our study raises the question whether shape driven FCC-to-BCC transitions are intrinsically first order.