Ferroelectric relaxation of theSrTiO3(100) surface

Abstract
The surface structure of SrTiO3(100) was analyzed at T=120 K by means of low-energy-electron diffraction. The best theory-experiment fit results for a surface containing domains of two different layer terminations. Both of them show a first-layer puckering with oxygen ions being pulled out of the surface by s(Ti)=0.08 Å and s(Sr)=0.16 Å combined with a relaxation of the first two layer distances. This proves the surface to be ferroelectric different from the bulk property in agreement with theoretical predictions.