Department of Physics and Astrophysics, University of Delhi, Delhi-110007, India.
Department of Physics, Kirori Mal College, University of Delhi, Delhi-110007, India.
Phys Chem Chem Phys. 2023 Feb 15;25(7):5857-5868. doi: 10.1039/d2cp04852c.
The inclusion of the spin-orbit coupling effect in ferroelectric materials with non-centrosymmetry leads to intriguing properties for spintronic applications. In the present work, a comparative study of spin splitting in the bulk electronic energy bands of the tetragonal and rhombohedral phases of BiFeO (BFO) in terms of the Rashba and Dresselhaus effects is carried out through first-principles calculations. The obtained spin splittings, particularly at the conduction band minima, are further supplemented with an effective · model analysis. For the tetragonal BFO, a dominating pure bulk-type Rashba effect with helical in-plane spin components shown through diagrams is observed, whereas the rhombohedral BFO shows a significant contribution from the out-of-plane spin components and an interplay between the Rashba and Dresselhaus effects is discussed. In addition, tunability of the Rashba parameters with the application of uniaxial strain (±5%) is obtained in tetragonal BFO, in which the Rashba coefficient () doubles with a compressive 5% strain, making tetragonal BFO a suitable candidate for spintronic applications. More importantly, full reversal of the in-plane spin texture is obtained for the opposite polarization states in tetragonal BFO with an activation energy barrier of 1.13 eV.
在非中心对称的铁电材料中加入自旋轨道耦合效应，为自旋电子学应用带来了有趣的性质。在本工作中，通过第一性原理计算，对四方相和三角相 BiFeO（BFO）的体电子能带中的自旋劈裂进行了 Rashba 和 Dresselhaus 效应的比较研究。得到的自旋劈裂，特别是在导带最小值处，进一步通过有效 · 模型分析进行了补充。对于四方相 BFO，观察到主导的纯体 Rashba 效应，具有螺旋平面内自旋分量，通过图表示。而三角相 BFO 则表现出明显的来自于垂直于平面的自旋分量的贡献，并讨论了 Rashba 和 Dresselhaus 效应之间的相互作用。此外，在四方相 BFO 中，通过施加单轴应变（±5%）获得了 Rashba 参数的可调谐性，其中 Rashba 系数（）在压缩 5%应变时增加了一倍，使得四方相 BFO 成为自旋电子学应用的合适候选材料。更重要的是，在四方相 BFO 中，对于相反的极化状态，通过 1.13 eV 的激活能垒，获得了完全相反的平面内自旋结构。
