Effect of electric field on negative linear expansion of ferroelectric-semiconductor TlGaSe2.

The effect of electric field on the thermal expansion of the TlGaSe₂ ferroelectric-semiconductor with a layer crystalline structure has been investigated. A strong transformation of negative linear expansion coefficient in the layer plane has been observed as a result of the applied electric field. It was concluded that internal electric fields created by local polarized states in the ferroelectric- semiconductor are responsible for a negative thermal expansion and its behavior under the electric field. Predominantly, the electrostriction effect is the driving mechanism of the lattice deformation of TlGaSe₂ crystals at low temperatures. [ABSTRACT FROM AUTHOR]