arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.09617cond-mat.mes-hallcond-mat.mtrl-sci
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SrTiO3-based异质结构中的可调自旋和轨道极化

Tunable spin and orbital polarization in SrTiO3-based heterostructures

Cong Son Ho, Weilong Kong, Ming Yang, Andrivo Rusydi, Mansoor B. A. Jalil

摘要:

本文推导了$\mathrm{LaAlO_3/SrTiO_3}$(LAO/STO)异质结中Rashba自旋轨道耦合(RSOC)的有效哈密顿量。我们推导出性质的解析表达式,例如,Rashba参数,有效质量,带边能量和轨道占有率,作为材料和可调异质结构参数的函数。虽然线性RSOC在$Γ$点附近占主导地位,但立方RSOC在较高能量的反交叉区域变得显著。我们发现,线性RSOC源于结构反转不对称(SIA),而立方项是由SIA和体积不对称引起的。此外,SOC的强度显示出一个惊人的依赖于可调异质结构参数,如STO的厚度和界面电场,这归因于附近的LAO/STO界面的量子限制效应。线性和立方RSOC的计算值与以前的实验结果一致。

英文摘要:

We formulate the effective Hamiltonian of Rashba spin-orbit coupling (RSOC) in $\mathrm{LaAlO_3/SrTiO_3}$ (LAO/STO) heterostructures. We derive analytical expressions of properties, e.g., Rashba parameter, effective mass, band edge energy and orbital occupancy, as functions of material and tunable heterostructure parameters. While linear RSOC is dominant around the $Γ$-point, cubic RSOC becomes significant at the higher-energy anti-crossing region. We find that linear RSOC stems from the structural inversion asymmetry (SIA), while the cubic term is induced by both SIA and bulk asymmetry. Furthermore, the SOC strength shows a striking dependence on the tunable heterostructure parameters such as STO thickness and the interfacial electric field which is ascribed to the quantum confinement effect near the LAO/STO interface. The calculated values of the linear and cubic RSOC are in agreement with previous experimental results.

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