Pressure induced structural phase transformation in TiN: a first-principles study

Bhat, Soumya S and Waghmare, Umesh V and Ramamurty, U (2013) Pressure induced structural phase transformation in TiN: a first-principles study. In: Journal of Applied Physics, 113 (13). 133507_1-133507_7.

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Abstract

Titanium nitride (TiN), which is widely used for hard coatings, reportedly undergoes a pressure-induced structural phase transformation, from a NaCl to a CsCl structure, at similar to 7 GPa. In this paper, we use first-principles calculations based on density functional theory with a generalized gradient approximation of the exchange correlation energy to determine the structural stability of this transformation. Our results show that the stress required for this structural transformation is substantially lower (by more than an order of magnitude) when it is deviatoric in nature vis-a-vis that under hydrostatic pressure. Local stability of the structure is assessed with phonon dispersion determined at different pressures, and we find that CsCl structure of TiN is expected to distort after the transformation. From the electronic structure calculations, we estimate the electrical conductivity of TiN in the CsCl structure to be about 5 times of that in NaCl structure, which should be observable experimentally. (C) 2013 American Institute of Physics. http://dx.doi.org/10.1063/1.4798591]

Item Type:	Journal Article
Publication:	Journal of Applied Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute of Physics.
Keywords:	AB Initio Calculations; Density Functional Theory; Electrical Conductivity; Electronic Structure; High-Pressure Solid-State Phase Transformations; Phonon Dispersion Relations; Titanium Compounds
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	31 May 2013 11:59
Last Modified:	31 May 2013 11:59
URI:	http://eprints.iisc.ac.in/id/eprint/46515

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