Electronic structure and stability of ordered vacancy phases of NbN
- Naval Research Lab., Washington, DC (United States). Complex Systems Theory Branch
A recently reported metastable phase of NbN with a superconducting T{sub c} = 16.4 K is characterized using full potential electronic structure methods. This new phase, which has Pm3m (cubic) symmetry, can be described as the B1 (rocksalt) structure with 25% ordered vacancies on each sublattice. They compare the equation of state and electronic spectrum of this Pm3m phase with its rocksalt counterpart and with Nb{sub 4}N{sub 3} in the I4/mm (tetragonal) phase, which allows the characterization of N vacancies without accompanying Nb vacancies. For Pm3m NbN, the calculated lattice constant is 5% smaller than reported and the energy is 1.00 eV/molecule higher than B1 NbN, suggesting that the newly reported phase is something other than a stoichiometric Pm3m phase of NbN. They report on the energy surface for tetragonal distortions of this phase, from which they evaluate its structural stability and obtain Poisson`s ratio.
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- OSTI ID:
- 489006
- Report Number(s):
- CONF-951155--; ISBN 1-55899-311-8
- Country of Publication:
- United States
- Language:
- English
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