Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan.
PRESTO, Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan.
Nat Commun. 2019 Jan 21;10(1):362. doi: 10.1038/s41467-018-08149-y.
Electrons in conventional metals become less mobile under the influence of electron correlation. Contrary to this empirical knowledge, we report here that electrons with the highest mobility ever found in known bulk oxide semiconductors emerge in the strong-correlation regime of the Dirac semimetal of perovskite CaIrO. The transport measurements reveal that the high mobility exceeding 60,000 cmVs originates from the proximity of the Fermi energy to the Dirac node (ΔE < 10 meV). The calculation based on the density functional theory and the dynamical mean field theory reveals that the energy difference becomes smaller as the system approaches the Mott transition, highlighting a crucial role of correlation effects cooperating with the spin-orbit coupling. The correlation-induced self-tuning of Dirac node enables the quantum limit at a modest magnetic field with a giant magnetoresistance, thus providing an ideal platform to study the novel phenomena of correlated Dirac electron.
在电子相关的作用下，传统金属中的电子变得不那么容易移动。与这一经验知识相反，我们在这里报告称，在钙钛矿 CaIrO 的狄拉克半金属的强关联区，发现了已知块状氧化物半导体中迁移率最高的电子。输运测量表明，超过 60,000 cmVs 的高迁移率源于费米能接近狄拉克节点（ΔE < 10 meV）。基于密度泛函理论和动态平均场理论的计算表明，随着系统接近莫特转变，能量差变得更小，这突出了关联效应与自旋轨道耦合协同作用的关键作用。关联引起的狄拉克节点自调谐使量子限制在适度的磁场中具有巨大的磁电阻，从而提供了一个理想的平台来研究关联狄拉克电子的新现象。
