Displacive Phase Transition in SrTiO3 Thin Films Grown on Si(001)
F S. Aguirre-Tostado, A Herrera-Gomez, Joseph Woicik, R Droopad, Z Yu, D G. Schlom, E Karapetrova, P Zschack
Polarization dependent x-ray absorption fine structure measurements performed at the Ti K edge together with x-ray diffraction have been used to study the local structure in SrTiO3 thin films grown epitaxially on Si(001). SrTiO3 layers on Si(001) are found to be unstrained for a thickness of approximately 80 A, a splitting of the Ti-O distance perpendicular to the interface is observed: rTiO = 1.87 +/- 0.02 and rTiO = 2.09 +/- 0.06 , whereas only a single Ti-O distance is observed within the plane of the interface: rTiO = 1.95 +/- 0.01 . These findings indicate a tetragonal plus displacive ferroelectric distortion of the cubic SrTiO3 unit cell in response to the compressive strain imposed on the SrTiO3 layer by the Si substrate. Modification of the Ti K pre-edge features are consistent with these findings.
, Herrera-Gomez, A.
, Woicik, J.
, Droopad, R.
, Yu, Z.
, Schlom, D.
, Karapetrova, E.
and Zschack, P.
Displacive Phase Transition in SrTiO<sub>3</sub> Thin Films Grown on Si(001), Letter to Nature
(Accessed December 1, 2021)