Quasiharmonic approach to a second-order phase transition

J. Łażewski, P. T. Jochym, P. Piekarz, and K. Parlinski
Phys. Rev. B 70, 104109 – Published 17 September 2004

Abstract

We present an ab initio based method of constructing the phase diagram of the second-order phase transitions with a significant volume dependence of the soft mode. This approach is based on the assumption that in the investigated crystal the phonon frequencies are mainly dependent on crystal volume and geometry. A critical volume for the transition at T=0K is derived from the crystal symmetry breaking point. The quasiharmonic approximation is used to find the free energy and the equation of state at finite temperature. The phase transition line is then the locus of points in the pT diagram corresponding to the critical volume. As an example we determine the pT phase diagram for CaCl2, which undergoes a rutile type—orthorhombic second-order phase transition.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 17 December 2003

DOI:https://doi.org/10.1103/PhysRevB.70.104109

©2004 American Physical Society

Authors & Affiliations

J. Łażewski*, P. T. Jochym, P. Piekarz, and K. Parlinski

  • Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland

  • *Author to whom correspondence should be addressed. Electronic address: jan.lazewski@ifj.edu.pl

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 70, Iss. 10 — 1 September 2004

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×