论文标题
通过数字（001）氧化物超晶格的新兴拓扑状态
Emergent topological states via digital (001) oxide superlattices
论文作者
论文摘要
氧化物异质结构具有许多有趣的特性。在这里，我们提供了在（001）中诱导多个拓扑状态的设计原理（$ a $ $ o $ _3 $）$ _ 1 $/（$ am'UM'U $ o $ _3 $）$ _ 1 $氧化物超级晶格。在第一原则计算和模型分析的帮助下，我们表明A（Sr $ M $ O3）$ _ 1 $/（Sr $ M'U $ O $ $ _3 $）$ _ 1 $ SUPERATTICE（$ M $ = NB，TA和$ M'U'$ = RH，IR，IR）是具有$ Z_2 $ INDEX（1; 1; 1; 001; 001; 001; 001; 001; 001; 001;更值得注意的是，（SRMOO3）$ _ 1 $/（SRIRO3）$ _ 1 $ SUPERPARTICE展示了多个共存的拓扑绝缘子（TI）和拓扑DIRAC半米（TDS）状态。 TDS状态在费米级附近具有一对I型DIRAC点，并具有对称性保护的Dirac节点线。表面TDS DIRAC锥由能量弹药空间中的两个表面Ti Dirac锥夹。非平凡的拓扑特性来自两个不同过渡金属原子的$ d $轨道之间的频段反转和（001）超级晶格几何形状的特定奇偶校验特性。我们的工作演示了如何通过理性设计在（001）钙钛矿氧化物异质结构中诱导非平凡的拓扑状态。
Oxide heterostructures exhibit many intriguing properties. Here we provide design principles for inducing multiple topological states in (001) ($AM$O$_3$)$_1$/($AM'$O$_3$)$_1$ oxide superlattices. Aided by first-principles calculations and model analysis, we show that a (Sr$M$O3)$_1$/(Sr$M'$O$_3$)$_1$ superlattice ($M$ = Nb, Ta and $M'$ = Rh, Ir) is a strong topological insulator with $Z_2$ index (1;001). More remarkably, a (SrMoO3)$_1$/(SrIrO3)$_1$ superlattice exhibits multiple coexisting topological insulator (TI) and topological Dirac semi-metal (TDS) states. The TDS state has a pair of type-II Dirac points near the Fermi level and symmetry-protected Dirac node lines. The surface TDS Dirac cone is sandwiched by two surface TI Dirac cones in the energy-momentum space. The non-trivial topological properties arise from the band inversion between $d$ orbitals of two dissimilar transition metal atoms and a particular parity property of (001) superlattice geometry. Our work demonstrates how to induce nontrivial topological states in (001) perovskite oxide heterostructures by rational design.
