Effects of pressure on structural, mechanical, and electronic properties of trigonal and monoclinic MgSiO3

Juan Gao, Wei Zeng, Bin Tang, Dai He Fan, Qi Jun Liu, Xiang Hui Chang, Mi Zhong

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We perform the first-principles calculation based on density-functional theory (DFT) to study the structural, electronic and mechanical properties of two MgSiO3 polymorphs (trigonal R‾3 and monoclinic P21/c) under pressure. The optimized lattice parameters of two MgSiO3 polymorphs under pressure are obtained and analyzed. Comparing the enthalpy values of the two structures under pressure, we find that monoclinic MgSiO3 will translate into trigonal structure in the range of 10 GPa–20 GPa. The relationship between the band structure and pressure is revealed. And we calculate the total density of state (TDOS) under different pressures and partial density of state (PDOS) under 0 GPa. The electron populations are obtained for trigonal and monoclinic MgSiO3. We systemically studied the mechanical properties of trigonal and monoclinic MgSiO3 under pressure including elastic constants, bulk modulus, shear modulus, Lamé's constants, Young's modulus, Poisson's ratio as well as B/G values. According to the modified Born stability conditions under pressure, trigonal MgSiO3 is stable from 0 GPa to 150 GPa, but monoclinic MgSiO3 is unstable from 80 GPa to 100 GPa.

Original languageEnglish
Article number106261
JournalSolid State Sciences
Volume105
DOIs
StatePublished - Jul 2020

Keywords

  • Electronic properties
  • First-principles calculations
  • Mechanical properties
  • MgSiO
  • Structural properties

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