Elasticity Profiles and High-Pressure Structural Transformations in Ultra-Incompressible Molybdenum Disilicide Polytypes

International Journal of Physics | Vol. 15, No. 2, September 2024 | pp. 65–72

DOI: 10.46882/2024/IJP/000173

Research Article

Title: Elasticity Profiles and High-Pressure Structural Transformations in Ultra-Incompressible Molybdenum Disilicide Polytypes

Names of Authors: V. I. Morozov¹, P. J. O’Connor²

Authors’ Affiliations:
¹ Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia
² Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland

Abstract: Evaluating ultra-incompressible structural alloys capable of maintaining structural stability under immense mechanical loading parameters is vital for industrial abrasive design and high-pressure geoscience anvil instrumentation. This paper investigates high-pressure elasticity profiles and monitors structural phase transformations in hexagonal and tetragonal molybdenum disilicide (MoSi2) polytypes up to hydrostatic pressures of 160.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework across compressed atomic configurations. At zero pressure, the calculated bulk modulus is B0 = 218.0 GPa, with an elastic pressure derivative value of B0' = 4.05, matching experimental diamond anvil cell measurements within a 1.2% margin. The single-crystal elastic constants (C11, C33, C44, C12, and C13) increase monotonically under uniform compression paths, satisfying all Born mechanical stability metrics across the entire tested pressure range. The directional compressibility paths reveal that the crystal c-axis displays exceptional stiffness due to short, covalent molybdenum-silicon bonds interlocking the rows. Electronic density calculations confirm a persistent metallic profile under ultra-high structural strain.

Keywords: Molybdenum disilicide; density functional theory; elastic constants; high pressure; structural stability; polytypes

Manuscript Timeline: Received: June 04, 2024; Revised: July 28, 2024; Accepted: August 18, 2024; Published: September 10, 2024

Citation: Morozov, V. I., & O’Connor, P. J. (2024). Elasticity Profiles and High-Pressure Structural Transformations in Ultra-Incompressible Molybdenum Disilicide Polytypes. International Journal of Physics, 15(9), 65–72.

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