Thermodynamic properties of 3C—SiC

Abstract

In the present paper, we report on the results of various thermodynamic properties of 3C-SiC at high pressure and temperature using first principles calculations. We use the plane-wave pseudopotential density functional theory as implemented in Quantum ESPRESSO code for calculating various cohesive properties in ambient condition. Further, ionic motion at a finite temperature is taken into account using the quasiharmonic Debye model. The calculated thermodynamic properties, phonon dispersion curves, and phonon densities of states at different temperatures and structural phase transitions at high pressures are found to be in good agreement with experimental and other theoretical results.

Equation of State of SiC at Extreme Conditions: New Insight Into the Interior of Carbon‐Rich Exoplanets

“…Noteworthy, the fine texture of our samples, highlighted by the continuous diffraction rings on our collected patterns, helps to unambiguously define the structural transition. Our findings clearly place the transition at 66 ± 2 GPa at room temperature and between 65 and 70 GPa at high temperature, in agreement with suggestion from previous LH DAC experiments (Daviau & Lee, ) and the computational work (Thakore et al, ). This transition pressure is significantly lower than earlier determination at ambient temperature by Yoshida et al () and the recent proposition at high temperature by Kidokoro et al ().…”

“…Our measurements are in agreement with previous reports in literature (e.g. Daviau & Lee 2017a, Thakore et al, 2013, Yoshida et al, 1993 and advocate for a structural transition from a cubic zinc-blende structure (B3) to a cubic rock-salt structure (B1), driven by a coordination change from tetrahedral to octahedral (Figure 2b).…”

“…Journal of Geophysical Research: Planets transition involves a significant volume reduction, with the value of the cell parameters changing, depending from actual temperature, from a = 4.09-4.10 Å (±0.002) (V = 68.80-69.06 (±0.1) Å 3 ) to a = 3.85-3.88 (±0.004) Å (V = 57.4-58.6 (±0.2) Å 3 ). Our measurements are in agreement with previous reports in literature (e.g., Daviau & Lee, 2017a;Thakore et al, 2013;Yoshida et al, 1993) and advocate for a structural transition from a cubic zinc-blende structure (B3) to a cubic rock-salt structure (B1), driven by a coordination change from tetrahedral to octahedral (Figure 2b).…”

“…Shock experiments studies locate the transition at higher pressure with respect to static experiments. According to the pioneering experimental study of Yoshida et al (), in the 3C polymorph, the phase transition takes place at 100 GPa under ambient temperature, while different computational studies instead indicate a pressure range between 60 and 80 GPa (Thakore et al, ). The latter value is also supported by the experimental work by Daviau and Lee (), which located the phase transition between 60 and 70 GPa.…”

Lattice Dynamical, Elastic, Thermodynamic Properties and Sound Velocities of 3C-SiC

“…Recently, the lattice dynamical properties of SiC in zinc-blende (ZB) phase are studied by many researchers using first principles methods [1][2][3][4] and phenomenological models [5,6]. But the exact information about dynamical properties is still missing.…”