International Journal of Physics | Vol. 5, No. 7, July 2014 | pp. 49–56
DOI: 10.46882/2014/IJP/000051
Research Article
Title: High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Osmium Diboride
Names of Authors: V. I. Morozov¹, J. K. Thornton²
Authors’ Affiliations: ¹Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow 142190, Russia; ²Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
Abstract: Designing ultra-incompressible materials capable of withstanding extreme mechanical stress is vital for industrial tooling and high-pressure research components. This paper examines the high-pressure elastic moduli and structural stability of orthorhombic osmium diboride (OsB²) up to hydrostatic pressures of 120.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework. At zero pressure, the calculated bulk modulus is B0 = 365.0 GPa, with an elastic derivative value of B0' = 4.12. These results match experimental diamond anvil cell measurements within a 1.5% margin. The single-crystal elastic constants (C11, C22, C33, C44, C55, and C66) increase monotonically under compression, satisfying all Born mechanical stability conditions across the tested pressure range. The directional compressibility curves reveal that the crystal c-axis is significantly stiffer than the a-axis and b-axis, which is due to short, covalent osmium-boron bonds aligned along the [001] plane. The electronic structure calculations show a high density of states at the Fermi level, indicating that OsB² retains its metallic character under high pressure. These precise elastic profiles confirm the potential of transition metal borides as viable alternatives to diamond-based superhard materials.
Keywords: Osmium diboride; density functional theory; elastic constants; high pressure; mechanical stability; directional compressibility
Manuscript Timeline: Received: March 15, 2014; Revised: May 02, 2014; Accepted: May 28, 2014; Published: July 11, 2014
Citation: Morozov, V. I., & Thornton, J. K. (2014). High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Osmium Diboride. International Journal of Physics, 5(7), 49–56.
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