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arXiv · 1106.4296

Interface engineering of quantum Hall effects in digital transition metal oxide heterostructures

Di Xiao·Wenguang Zhu·Ying Ran·Naoto Nagaosa·Satoshi Okamoto
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Abstract

Topological insulators are characterized by a nontrivial band topology driven by the spin-orbit coupling. To fully explore the fundamental science and application of topological insulators, material realization is indispensable. Here we predict, based on tight-binding modeling and first-principles calculations, that bilayers of perovskite-type transition-metal oxides grown along the [111] crystallographic axis are potential candidates for two-dimensional topological insulators. The topological band structure of these materials can be fine-tuned by changing dopant ions, substrates, and external gate voltages. We predict that LaAuO$_3$ bilayers have a topologically-nontrivial energy gap of about 0.15 eV, which is sufficiently large to realize the quantum spin-Hall effect at room temperature. Intriguing phenomena, such as fractional quantum Hall effect, associated with the nearly-flat topologically-nontrivial bands found in $e_g$ systems are also discussed.

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Di Xiao, Wenguang Zhu, Ying Ran, Naoto Nagaosa, Satoshi Okamoto. 2011-06-21. Interface engineering of quantum Hall effects in digital transition metal oxide heterostructures. https://doi.org/10.1038/ncomms1602

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