SOFT PHONON MODE IN SNTE

The self-consistent phonon formalism, successful in the description of the quantum crystals He3 and He4, is here applied to a discussion of the soft k=0 TO mode in SnTe. Straightforward considerations allow us to arrive at a simple expression for ωTO2(k=0) in the low-temperature regime. The analysis permits a quantitative fit to the temperature dependence of ωTO2(k=0) over a rather wide range of temperature. © 1969 The American Physical Society.