First-Principles Study of Structure, Vibrational, and Elastic Properties of Stoichiometric and Calcium-Deficient Hydroxyapatite

Bhat, Soumya S and Waghmare, Umesh V and Ramamurty, Upadrasta (2014) First-Principles Study of Structure, Vibrational, and Elastic Properties of Stoichiometric and Calcium-Deficient Hydroxyapatite. In: CRYSTAL GROWTH & DESIGN, 14 (6). pp. 3131-3141.

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Abstract

Hydroxyapatite (HAp), a primary constituent of human bone, is usually nonstoichiometric with varying Ca/P molar ratios, with the well-known fact that Ca deficiency can cause marked reductions in its mechanical properties. To gain insights into the mechanism of this degradation, we employ first-principles calculations based on density functional theory and determine the effects of Ca deficiency on structure, vibrational, and elastic properties of HAp. Our simulation results confirm a considerable reduction in the elastic constants of HAp due to Ca deficiency, which was experimentally reported earlier. Stress-induced transformation of the Ca-deficient defected structure into a metastable state upon the application of stress could be a reason for this. Local structural stability of HAp and Ca-deficient HAp structures is assessed with full phonon dispersion studies. Further, specific signatures in the computed vibrational spectra for Ca deficiency in HAp can be utilized in experimental characterization of different types of defected HAp.

Item Type:	Journal Article
Publication:	CRYSTAL GROWTH & DESIGN
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, USA.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	16 Jul 2014 08:57
Last Modified:	16 Jul 2014 08:57
URI:	http://eprints.iisc.ac.in/id/eprint/49426

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