Unique electronic structures found at materials interfaces can allow unconventional quantum states to emerge. In a new report on Science, Changjiang Liu and a research team at the Argonne National Laboratory, University of Illinois and the Chinese Academy of Sciences detailed the discovery of superconductivity in electron gases formed at the interfaces between potassium tantalate (KTaO3) and insulating overlayers of either Europium-II oxide (EUO) or lanthanum aluminate (LaAlO3). The superconducting transition temperature approaching 2.2 K observed in this work was an order of magnitude higher than previous systems of lanthanum aluminate/strontium titanate. The critical field and current-voltage measurements indicated the two-dimensional (2-D) character of superconductivity. The team noted a spontaneous in-plane transport anisotropy in the EUO/ KTaO3 samples prior to the onset of superconductivity to suggest the emergence of a distinct ‘stripe’ like phase near the critical field.
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Source: Phys.org