International Journal of Physics

International Journal of Physics | Vol. 11, No. 4, April 2020 | pp. 25–32

DOI: 10.46882/2020/IJP/000120

Research Article

Title: High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Molybdenum Disilicide

Names of Authors: V. I. Morozov¹, K. A. Tanaka²

Authors’ Affiliations:
¹ Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia
² Department of Physics, Tokyo Institute of Technology, Tokyo, Japan

Abstract: Designing ultra-incompressible structural 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 tetragonal molybdenum disilicide (MoSi²) up to hydrostatic pressures of 130.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework. At zero pressure, the calculated bulk modulus is B0 = 215.0 GPa, with an elastic derivative value of B0' = 4.15. These results match experimental diamond anvil cell measurements within a 1.5% margin. The single-crystal elastic constants (C11, C33, C44, C66, C12, and C13) 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, which is due to short, covalent molybdenum-silicon bonds aligned along the plane. The electronic structure calculations show a high density of states at the Fermi level, indicating that MoSi² retains its metallic character under high pressure. These precise elastic profiles confirm the potential of transition metal silicides as viable alternatives to conventional superhard materials.

Keywords: Molybdenum disilicide; density functional theory; elastic constants; high pressure; mechanical stability; directional compressibility

Manuscript Timeline: Received: January 04, 2020; Revised: February 17, 2020; Accepted: March 09, 2020; Published: April 10, 2020

Citation: Morozov, V. I., & Tanaka, K. A. (2020). High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Molybdenum Disilicide. International Journal of Physics, 11(4), 25–32.

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