The thermodynamic functions of ferroelectric and paraelectric SbSI

Abstract

A first-principle method is used to calculate phonon density of states, Helmholtz free energy, internal energy, and entropy for ferroelectric and paraelectric SbSI. Theoretical phase transition temperature was obtained using the difference of the Helmholtz free energy, internal energy, and entropy term between ferroelectric and paraelectric phases on temperature. The obtained value is in reasonable agreement with the experimental second-order phase transition temperature T_c2 = 233 K.

Keywords:

• SbSI
• phase transitions
• phonons
• free energy
• entropy

PACS:

• 63.20.D−
• 65.40.−b
• 71.15.Mb
• 77.80.B−