Durandurdu, Murat2024-09-022024-09-02202409270256https://doi.org/10.1016/j.commatsci.2024.113062https://hdl.handle.net/20.500.12573/2367Employing constant pressure ab initio simulations, we have shed light on the previously unknown high-pressure behavior of amorphous gallium nitride. Our findings reveal a two-step transformation sequence under pressure. The initial transition involves a polyamorphic transformation from a low-density amorphous (LDA) phase to a high-density amorphous (HDA) phase with an average coordination number of 5.4. Upon pressure release, the HDA state partially reverts to a denser amorphous network with a higher coordination number (4.34) compared to the original LDA phase. Further pressurization triggers the crystallization of the HDA state into a rocksalt structure. Remarkably, the electronic structure of the amorphous forms of GaN exhibits insignificant sensitivity to changes in coordination number, maintaining a band gap of approximately 1.7–2.0 eV across all phases.enginfo:eu-repo/semantics/closedAccessGallium nitrideAmorphousPolyamorphismarticle24118