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Theoretical Prediction of Post‐Spinel Phases of Silicon Nitride
Author(s) -
Tatsumi Kazuyoshi,
Tanaka Isao,
Adachi Hirohiko,
Oba Fumiyasu,
Sekine Toshimori
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00029.x
Subject(s) - spinel , pseudopotential , materials science , phase (matter) , silicon , silicon nitride , band gap , nitride , bulk modulus , thermodynamics , analytical chemistry (journal) , condensed matter physics , chemistry , nanotechnology , composite material , metallurgy , optoelectronics , physics , organic chemistry , layer (electronics) , chromatography
New phases of Si 3 N 4 that may be stable at higher pressure than spinel have been searched using a first‐principles plane‐wave pseudopotential method. The CaTi 2 O 4 ‐type phase is found to be the prime candidate for the post‐spinel phase among six phases selected on the analogy to high‐pressure oxides. The phase transformation from the spinel is predicted to occur at 210 GPa. All silicon atoms of the new phase are coordinated by six anions, similar to the case of the high‐pressure forms of SiO 2 and SiC. Because of its high energy at zero pressure, this new phase may be difficult to quench. The bandgap increases with an increase of pressure when compared in the same polymorph. However, the bandgap and the net charge decrease in the order of β, spinel, and CaTi 2 O 4 ‐type phases at zero pressure. The theoretical bulk modulus of the CaTi 2 O 4 ‐type phase is comparable with that of spinel.