A Monash University-led research team has discovered that a structure comprising an ultra-thin topological insulator sandwiched between two 2D ferromagnetic insulators becomes a large-bandgap quantum anomalous Hall insulator.
Such a heterostructure provides an avenue towards viable ultra-low energy future electronics, or even topological photovoltaics.
In the researchers' new heterostructure, a ferromagnetic material forms the 'bread' of the sandwich, while a topological insulator (ie, a material displaying nontrivial topology) takes the place of the 'filling'.
Combining magnetism and nontrivial band topology gives rise to quantum anomalous Hall (QAH) insulators, as well as exotic quantum phases such as the QAH effect where current flows without dissipation along quantized edge states.
Inducing magnetic order in topological insulators via proximity to a magnetic material offers a promising pathway towards achieving QAH effect at higher temperatures (approaching or exceeding room temperature) for lossless transport applications.
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