Structural phase transitions in solids with applied stresses and fields, and effect of isotopic impurities on the free energy Academic Article uri icon


  • Subject to the assumptions described in the text, we obtain the following expression for the transition temperature Tc associated with a structural phase transition: Tc=α(ΔU+Σ iΡiΔαi)kB, α≡2/In(|Φ|/Φ′|). Here ΔU is the change in energy, the Pi are given by the pressure, stresses, and applied fields, the Δαi, are given by the changes in volume, strains, and dipole moments, and |Φ| is the determinant of the force constant matrix. We also give a result which may be useful for solids containing isotopic impurities: At high temperatures and in the harmonic approximation, ΔG=-(3/2)kBT Σkl(mk′/m k) here ΔG is the change in Gibbs free energy when some of the particle masses are changed from mk to mk′. Copyright © 1976 American Institute of Physics.

author list (cited authors)

  • Allen, R. E.

citation count

  • 3

publication date

  • January 1976