Synthesis and novel properties of Q-silicon (January 2023)

We report the discovery of Q-silicon with an atomic density of 60% higher than crystalline silicon while keeping the bonding characteristics the same as normal silicon. Distinct amorphous phases are created, when one, two, or three tetrahedra are randomly packed, and a crystalline phase of Q silicon is formed when subunit cells are arranged along < 110 > directions with alternate holes. Nanosecond laser melting of amorphous silicon in an undercooled state and quenching have created Q-silicon with robust ferromagnetism compared to the diamagnetism of silicon. The blocking temperature of Q-silicon is estimated to be over 400 K, thus opening a new frontier for spin-based computing and atomic-level storage.