Semiconducting Cubic Titanium Nitride in the Th3P4 Structure

Stephan Lany, Venkata Bhadram, Hanyu Liu, Enshi Xu, Tianshu Li, Vitali Prakapenka, Rostislav Hrubiak, Timothy Strobel

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26 Scopus Citations

Abstract

We report the discovery of a long-sought-after phase of titanium nitride with stoichiometry Ti3N4 using diamond anvil cell experiments combined with in situ high-resolution x-ray diffraction and Raman spectroscopy techniques, supported by ab initio calculations. Ti3N4 crystallizes in the cubic Th3P4 structure [space group I43d (220)] from a mixture of TiN and N2 above ≈75 GPa and ≈2400 K. The density (≈5.22 g/cc) and bulk modulus (K0=290 GPa) of cubic-Ti3N4 (c-Ti3N4) at 1 atm, estimated from the pressure-volume equation of state, are comparable to rocksalt TiN. Ab initio calculations based on the GW approximation and using hybrid functionals indicate that c-Ti3N4 is a semiconductor with a direct band gap between 0.8 and 0.9 eV, which is larger than the previously predicted values. The c-Ti3N4 phase is not recoverable to ambient pressure due to dynamic instabilities, but recovery of Ti3N4 in the defect rocksalt (or related) structure may be feasible.

Original languageAmerican English
Article number011602
Number of pages5
JournalPhysical Review Materials
Volume2
Issue number1
DOIs
StatePublished - 22 Jan 2018

Bibliographical note

Publisher Copyright:
© 2018 American Physical Society.

NREL Publication Number

  • NREL/JA-5K00-70919

Keywords

  • first-principles
  • Monte-Carlo
  • photovoltaics

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