Siemons Wolter, Koster Gertjan, Yamamoto Hideki, Harrison Walter A, Lucovsky Gerald, Geballe Theodore H, Blank Dave H A, Beasley Malcolm R
Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA.
Phys Rev Lett. 2007 May 11;98(19):196802. doi: 10.1103/PhysRevLett.98.196802. Epub 2007 May 8.
As discovered by Ohtomo and Hwang, a large sheet charge density with high mobility exists at the interface between SrTiO3 and LaAlO3. Based on transport, spectroscopic, and oxygen-annealing experiments, we conclude that extrinsic defects in the form of oxygen vacancies introduced by the pulsed laser deposition process used by all researchers to date to make these samples is the source of the large carrier densities. Annealing experiments show a limiting carrier density. We also present a model that explains the high mobility based on carrier redistribution due to an increased dielectric constant.
正如大友和黄所发现的，在SrTiO₃和LaAlO₃的界面处存在具有高迁移率的大面电荷密度。基于输运、光谱和氧退火实验，我们得出结论，迄今为止所有研究人员用于制备这些样品的脉冲激光沉积过程所引入的氧空位形式的外在缺陷是大载流子密度的来源。退火实验显示了一个极限载流子密度。我们还提出了一个基于介电常数增加导致载流子重新分布来解释高迁移率的模型。
