High-Pressure Elastic Moduli and Structural Transitions in Ultra-Incompressible Tantalum Diboride

International Journal of Physics | Vol. 13, No. 3, March 2022 | pp. 17–24

DOI: 10.46882/2022/IJP/000143

Research Article

Title: High-Pressure Elastic Moduli and Structural Transitions in Ultra-Incompressible Tantalum Diboride

Names of Authors: V. I. Morozov¹, D. L. Santos²

Authors’ Affiliations:
¹ Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia
² Department of Physics, University of Coimbra, Coimbra, Portugal

Abstract: Synthesizing ultra-incompressible refractory materials capable of retaining structural integrity under extreme mechanical stress and shear paths is vital for aerospace components and industrial drill systems. This paper examines the high-pressure elastic moduli and evaluates structural transitions in hexagonal tantalum diboride (TaB₂) up to hydrostatic pressures of 140.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework across compressed lattice profiles. At zero pressure, the calculated bulk modulus is B0 = 291.0 GPa, with an elastic derivative value of B0' = 4.10, matching experimental diamond anvil cell measurements within a 1.2% margin. The single-crystal elastic constants (C11, C33, C44, C12, and C13) climb linearly under volumetric compression, matching all Born mechanical stability criteria across the tested pressure limits. The directional compressibility curves show that the crystal c-axis displays exceptional rigidity due to short, highly covalent tantalum-boron networks interlocking the basal atomic planes. Electronic density of states charts verify a large population at the Fermi edge, proving that TaB₂ retains its metallic profile under ultra-high structural strain.

Keywords: Tantalum diboride; density functional theory; elastic constants; high pressure; mechanical stability; directional compressibility

Manuscript Timeline: Received: December 14, 2021; Revised: January 20, 2022; Accepted: February 08, 2022; Published: March 11, 2022

Citation: Morozov, V. I., & Santos, D. L. (2022). High-Pressure Elastic Moduli and Structural Transitions in Ultra-Incompressible Tantalum Diboride. International Journal of Physics, 13(3), 17–24.

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