A series of layered intergrowth phases grown by molecular beam epitaxy:: SrmTiO2+m(m=1-5)

SrmTiO2+m phases having one TiO2 layer sandwiched between m SrO layers were grown using molecular beam epitaxy. The out-of-plane (in-plane) lattice parameters determined by x-ray diffraction were c(a)=9.14 A (3.78 A), 23.55 A (3.75 A), and 14.60 A (3.75 A) for Sr3TiO5, Sr4TiO6, and Sr5TiO7, respectively. Both lattice parameters change abruptly on going from the m=2 Ruddlesden-Popper phase to m=3 phase, indicating a significant change in the bond lengths (or strain states) on transitioning from the known members to the higher order members of this structural family. Electron microscopy confirmed the artificially layered structures.