Effect of intrinsic point defects on ferroelectric polarization behavior of SrTiO3
Effect of intrinsic point defects on ferroelectric polarization behavior of SrTiO3
复制标题
DOI：
10.1103/physrevb.95.035301
复制
发表时间：
2017-01-04
影响因子：
3.7
通讯作者：
Alexandrov, Vitaly
中科院分区：
文献类型：
--
作者：
Klyukin, Konstantin;Alexandrov, Vitaly
通过基于密度泛函理论的计算和 Berry 相方法，研究了 SrTiO3 块体和薄膜中的各种本征缺陷和缺陷簇对铁电极化和开关机制的影响。结果表明，钛Ti-Sr（中心点中心点）和锶Sr-Ti（“）Ti反位缺陷都会引起SrTiO3中的铁电极化，其中Ti-Sr（中心点中心点）缺陷比Sr-Ti（”）引起更明显的自发极化和更高的极化反转激活势垒。与反位缺陷结合的氧空位的存在可以增强或减弱极化，具体取决于缺陷对的配置，但与没有氧空位的反位缺陷相比，它总是导致更大的极化切换激活势垒。我们还表明，SrTiO3 中自发极化的大小可以通过控制 Sr/Ti 非化学计量的程度来调节。其他本征点缺陷，例如弗伦克尔缺陷对和电子小极化子，也有助于 SrTiO3 中铁电极化的出现。
The effect of a variety of intrinsic defects and defect clusters in bulk and thin films of SrTiO3 on ferroelectric polarization and switching mechanisms is investigated by means of density-functional-theory based calculations and the Berry phase approach. Our results show that both the titanium Ti-Sr(center dot center dot) and strontium Sr-Ti(") Ti antisite defects induce ferroelectric polarization in SrTiO3, with the Ti-Sr(center dot center dot) defect causing a more pronounced spontaneous polarization and higher activation barriers of polarization reversal than Sr-Ti("). The presence of oxygen vacancies bound to the antisite defects can either enhance or diminish polarization depending on the configuration of the defect pair, but it always leads to larger activation barriers of polarization switching as compared to the antisite defects with no oxygen vacancies. We also show that the magnitude of spontaneous polarization in SrTiO3 can be tuned by controlling the degree of Sr/Ti nonstroichiometry. Other intrinsic point defects such as Frenkel defect pairs and electron small polarons also contribute to the emergence of ferroelectric polarization in SrTiO3.