Large Rashba spin-orbit coupling in metallic SrTaO$_3$ thin films
| Autor: | Okuma, Hikaru, Katayama, Yumiko, Kadowaki, Fukunobu, Tokumoto, Yuki, Ueno, Kazunori |
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| Rok vydání: | 2024 |
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| Druh dokumentu: | Working Paper |
| Popis: | Epitaxial thin films of SrTaO$_3$ with thickness ($t$) smaller than 74 nm were successfully fabricated on an insulator (LaAlO$_3$)$_{0.3}$(Sr$_2$AlTaO$_6$)$_{0.7}$ substrate. Films with $t$ above 8.6 nm showed metallic conduction. Both conductivity and a mobility showed a decrease with increasing $t$ above 42 nm, suggesting the instability of thick SrTaO$_3$ films. This instability was also supported by TEM image and XRD intensity. For the metallic films with $t$ below 25 nm, energy band splitting due to spin-orbit coupling ($\Delta$$_{so}$) and Rashba parameter ($\alpha$$_R$) were deduced from an analysis of a magnetoresistance using two-dimensional weak antilocalization theory. The values of $\Delta$$_{so}$ ranged from 26 to 120 meV, which were the largest among other metallic oxide films, such as SrNbO$_3$, SrIrO$_3$, and La$_{2/3}$Sr$_{1/3}$MnO$_3$ thin films, indicating that spin-orbit coupling in SrTaO$_3$ was the largest among the metallic perovskite oxides reported so far. The values of $\alpha$$_R$ for our SrTaO$_3$ films ranged from $8.8 \times$10$^{-13}$ to $1.7 \times$10$^{-12}$ eV m, which were much larger than those reported for other metallic oxide thin films. Comment: 17 pages, 8 figures |
| Databáze: | arXiv |
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