Possibility of a noncommensurate phase near the
transition point in quartz
Aslanyan T.A., Levanyuk A.P.
The possibility is considered of formation of a long-period incommensurate superstructure near the α++β transition point in quartz. Account is taken of the interaction of the soft phonon branch with the acoustic branch. An essential role is played here by the decrease of the modulus of hydrostatic compression near the transition point, as established by fluctuation effects.