Theoretical study on isostructural pressure-induced phase transition of solid ethane at extremely low temperature

The stable crystalline phase of ethane at atmospheric pressure can only exist at extremely low temperatures, but the pressure-induced phase transition of ethane at these low temperatures has received little attention from researchers. Based on the calculations of Raman vibrational modes and 2D fingerprints of P2₁/n-C₂H₆ under different pressures, we found that ethane at 0 K exhibits an isostructural phase transition under 3 GPa. The extremely low temperature (0 K) suppresses the appearance of room temperature crystalline plastic phase A but promotes the higher-pressure phase B at the lower pressure point.