Influence of polytypism on structural phase transformations in TlGaSe2 crystals

摘要

The polytypism is found to have a significant influence on the structural transformation of the crystal lattice of the TlGaSe2 ferroelectric with variations in temperature. In the 2C-polytype, unlike the C-polytype, a first-order structural phase transition, which leads to a change in the translational symmetry along the C axis, is not observed in the temperature range T = 90-300 K and a second-order phase transition due to the formation of an incommensurate phase occurs at a higher temperature.