Phys.org April 27, 2021
The distinctive electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. An international team of researchers (USA – Argonne National Laboratory, University of Illinois, China) has discovered superconductivity in electron gases formed at interfaces between (111)-oriented KTaO3 and insulating overlayers of either EuO or LaAlO3. The superconducting transition temperature, as high as 2.2 kelvin, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Similar electron gases at KTaO3 (001) interfaces remain normal down to 25 millikelvin. The critical field and current-voltage measurements indicated that the superconductivity is two-dimensional. In EuO/KTaO3 (111) samples, they observed a spontaneous in-plane transport anisotropy before the onset of superconductivity, suggesting the emergence of a distinct “stripe”-like phase, which is also revealed near the critical field…read more. TECHNICAL ARTICLE
Superconducting state discovered at interfaces with (111) oriented KTaO3 surfaces, which has a buckled honeycomb lattice… Credit: Anand Bhattacharya/Argonne National Laboratory.