  Materials adopting the diamond structure possess useful properties in atomic
and colloidal systems, and are a popular target for synthesis in colloids where
a photonic band gap is possible. The desirable photonic properties of the
diamond structure pose an interesting opportunity for reconfigurable matter:
can we create a colloidal crystal able to switch reversibly to and from the
diamond structure? Drawing inspiration from high-pressure transitions of
diamond-forming atomic systems, we design a system of polyhedrally-shaped
particles that transitions from diamond to a tetragonal diamond derivative upon
a small pressure change. The transition can alternatively be triggered by
changing the shape of the particle in-situ. We propose that the transition
provides a reversible reconfiguration process for a potential new colloidal
material, and draw parallels between this transition and phase behavior of the
atomic transitions from which we take inspiration.
