Designing iridate-based superlattice with large magnetoelectric coupling
Designing iridate-based superlattice with large magnetoelectric coupling
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DOI：
10.1039/c9tc04466c
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发表时间：
2019-11-14
影响因子：
6.4
通讯作者：
Xu, Haixuan
中科院分区：
文献类型：
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作者：
Dasa, Tamene R.;Hao, Lin;Xu, Haixuan
铁电有序和磁性有序之间的耦合为利用电场控制磁性提供了有力的手段。在这项研究中，我们用第一性原理密度泛函理论(DFT)计算了Ir酸盐-氧化物超晶格中的磁电耦合。特别是，我们研究了几种氧化物超晶格，包括(SrIrO_3)(1)-(CaTiO_3)(1)(SiO-CTO)和(SrIrO_3)(1)-(BaTiO_3)(1)(SiO-BTO)，其中SiO和CTO/BTO交替单层。我们在SiO-BTO中发现了一个非常大的ME耦合，它是由晶格贡献和电子贡献共同作用的。相比之下，在SiO-CTO中发现了中等的ME耦合常数。进一步的电子和结构分析表明，SiO-BTO的大的ME耦合是由5DIr的大的自旋-轨道耦合以及SiO-BTO的显著极化引起的。有趣的是，我们发现通过调制外延应变可以进一步增强SiO-BTO中的ME耦合。这些结果给出了一条显著增强ME耦合效应的途径，这可能适用于其他材料和实际应用。
The coupling between ferroelectric and magnetic order provides a powerful means to control magnetic properties with electric fields. In this study, we have investigated the magnetoelectric (ME) coupling in iridate-oxide based superlattices employing first-principles density functional theory (DFT) calculations. In particular, we have investigated several oxide superlattices, including (SrIrO3)(1)-(CaTiO3)(1) (SIO-CTO) and (SrIrO3)(1)-(BaTiO3)(1) (SIO-BTO), with an alternating single layer of SIO and CTO/BTO. We identify a very large ME coupling in SIO-BTO mediated by both lattice and electronic contributions. In comparison, moderate ME coupling constants are found in SIO-CTO. Further electronic and structural analyses reveal that the large ME coupling of SIO-BTO is caused by the large spin-orbit coupling of 5d iridium as well as the significant polarization induced in the SIO-BTO. Interestingly, we find that the ME coupling in SIO-BTO can further be enhanced by modulating epitaxial strain. These results suggest a route to significantly enhance the ME coupling effects, which might be applicable for other materials and practical applications.