Origin of Pressure-Induced Metallization in Cu3N: An X-ray Absorption Spectroscopy Study
View/ Open
Author
Kuzmin, Alexei
Anspoks, Andris
Kalinko, Aleksandr
Timoshenko, Janis
Nataf, Lucie
Baudelet, François
Irifune, Tetsuo
Date
2018Metadata
Show full item recordAbstract
High-pressure (0–26.7 GPa) Cu K-edge X-ray absorption spectroscopy is used to study possible structural modifications of anti-perovskite-type copper nitride (Cu3N) crystal lattice. The analysis of X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), based on theoretical full-multiple-scattering and single-scattering approaches, respectively, suggests that at all pressures the local atomic structure of Cu3N remains close to that in cubic (Formula presented.) phase. Therefore, the transition to metal state above 5 GPa, observed previously using pressure-dependent electrical resistance and optical absorption measurements, is explained by the band gap collapse due to a decrease of the unit cell volume. We found that the lattice parameter of Cu3N is reduced by ≈2% upon increasing pressure up to 26.7 GPa, and the structure is restored upon pressure release.