BARC/PUB/2019/0305

 
 

Shock induced phase transition in SiC polytypes

 
     
 
Author(s)

Gorai, S.; Bhattacharya, C.
(ThPS)

Source

Journal of Applied Physics, 2019. Vol. 125: Article no. 185903

ABSTRACT

The effect of shock on 3C and 6H phases of silicon carbide was investigated within our earlier developed scaled binding energy based Debye– Gr€uneisen model. Required input parameters for the equation of state (EOS) model were obtained from density functional theory calculations using PBE-GGA functional as well as a nonlocal exchange-correlation functional B3LYP. In our earlier calculations using PBE-GGA functional, we predicted the phase transition from 3C to B1 phase at about 68 GPa, which deviated significantly from the experimental value of about 100 GPa. An empirical energy correction was applied in that case to obtain the experimental transition pressure. However, in the present work, we observed that if hybrid B3LYP functional is employed to calculate EOS parameters, shock induced phase transitions from 3C to B1 and 6H to B1 phases occur at about 102 GPa and 105 GPa, respectively, in close agreement with experiments without invoking any empirical correction. We obtained good agreement of our predictions with experimental shock data using a simple model of metastability and the hybrid B3LYP functional, which accounts for exchange-correlation effects better than the PBE-GGA functional in the case of SiC.

 
 
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