Phase change observed in ultrathin Ba0.5Sr0.5TiO3 films by in situ resonant photoemission spectroscopy

作者：Lin Y H^*; Terai K; Wadati H; Kobayashi M; Takizawa M; Hwang J I; Fujimori A; Nan C W; Li J F; Fujimori S I; Okane T; Saitoh Y; Kobayashi K

来源：Applied Physics Letters, 2007, 90(22): 222909.

DOI：10.1063/1.2745249

Epitaxial Ba0.5Sr0.5TiO3 thin films were prepared on Nb-doped SrTiO3 (100) substrates by the pulsed laser deposition technique and were studied by measuring the Ti 2p -> 3d resonant photoemission spectra in the valence-band region as a function of film thickness, both at room temperature and low temperature. The results demonstrated an abrupt variation in the spectral structures between 2.8 nm (similar to 7 ML) and 2.0 nm (similar to 5 ML) Ba0.5Sr0.5TiO3 films, suggesting that there exists a critical thickness for phase change in the range of 2.0-2.8 nm. This may be ascribed mainly to the intrinsic size effects.

• 出版日期2007-5-28
• 单位清华大学