应力作用下铁电超晶格BaTiO_3/SrTiO_3的结构和极化的第一性原理研究

First-principles study of structural instability and polarization in BaTiO_3/SrTiO_3 superlattice

通过第一性原理计算,研究了在不同应力作用下铁电超晶格BaTiO3/SrTiO3的结构以及自发极化的变化.结果显示,在应力作用下,晶格发生变形,并且沿着c轴在Ti原子和O原子之间电荷发生传输.随着应力的增加,超晶格中各类原子沿着c轴的位移都会有不同程度上的增加,造成了铁电超晶格的自发极化不断提高.此外,在该模型中,通过变化所施加的应力,可以控制超晶格的极化性质.

We investigated structural instability and polarization of BaTiO3/SrTiO3 superlattice under stress by using first-principles calculation. Our results show that stress induces lattice distortion and charge transfer between Ti atom and O atom. With stress increasing,atomic displacement in BaTiO3/SrTiO3 superlattice grows gradually, resulting in the enhancement of polarization. Furthermore, polarization of superlattice BaTiO3/SrTiO3 can be controlled by changing the stress.