Structural transition of Li3N under high pressure: A first-principles study

We theoretically study the electronic properties and pressure induced solid-solid phase transition of Li3N by first-principles calculations. The calculations indicate a pressure-induced structural phase transition above 1.5GPa from the ambient P6/MMM hexagonal phase (alpha-Li3N) to a layered hexagonal phase (beta-Li3N, P63/MMC) which is accompanied by a 21.6% volume collapse. Above 38.8 GPa, beta-Li3N transforms into gamma-Li3N(Fm (3) over barm), and the recently reported new alpha'-phase (P-3M1) is not stable under high pressure. The analysis of electronic density of states suggests that various Li3N polymorphs are insulators, and the band gap is broadened with further compression. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.