SrTiO3中俘获电子与自由电子的共存
Coexistence of trapped and free excess electrons in SrTiO3
摘要：
SrTiO 3中的过量电子是形成自由载流子还是形成俘获载流子的问题是这种重要材料的电子性质的一个关键方面。这种基本的模糊性阻碍了对令人困惑的实验情况的一致解释，在这种情况下，结果支持一种或另一种情况，这取决于所进行的实验类型。利用密度泛函理论修正了原位库仑相互作用U，它建立了多余的电子形成小极化子，如果电子密度高于~1%。对于低于这个临界值的密度，电子保持离域或变成大的极化子。我们的缺氧SrTiO 3的建模提供了一个替代图片相对于以前的理论研究赋予坚实的证据，所观察到的，温度驱动的金属-绝缘体转变的样品中均匀分布的氧空位。局限于Ti（3+）位点的小极化子在低温下是不动的，但可以被热激活成导电状态。
英文摘要：
The question whether excess electrons in SrTiO3 form free or trapped carriers is a crucial aspect for the electronic properties of this important material. This fundamental ambiguity prevents a consistent interpretation of the puzzling experimental situation, where results support one or the other scenario depending on the type of experiment that is conducted. Using density functional theory corrected with an on-site Coulomb interaction U, it is established that excess electrons form small polarons if the electron density is higher than ~ 1%. For densities below this critical value, the electrons stay delocalized or become large polarons. Our modeling of oxygen deficient SrTiO3 provides an alternative picture with respect to previous theoretical studies endowing firm evidence for the observed, temperature-driven metal-insulator transition in samples with homogeneously distributed oxygen vacancies. Small polarons confined to Ti(3+) sites are immobile at low temperature but can be thermally activated into a conductive state.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
