Thermal conductivity measurements have been carried out on single crystals of SrTiO3 and KTaO3 in the presence of electric fields applied either perpendicular or parallel to the heat current. In the case of SrTiO3, the response is surprisingly large: a 7 kV/cm parallel field increases the thermal conductivity by up to 400%. A pronounced anisotropy in both materials, which becomes apparent above nearly the same temperature, is also observed. These effects can be interpreted qualitatively using a simple model in which TA phonons in an energy band near the soft TO mode scatter off of either impurities, ferroelectric microregions, or quantum ferroelectric fluctuations.
|Original language||English (US)|
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Oct 1 2000|