Recent Research

Electronic phase separation for the interface superconductivity in LaAlO3/SrTiO3

Post Date:2020-03-16

The formation of Cooper pairs can be more favorable for electrons from certain orbitals, giving rise to an unusual state with the coexistence of normal fluid and superfluid. In a recent work led by Dr. Wei-Li Lee and Dr. Sungkit Yip, such a phase is likely to happen for the interface superconductivity in LaAlO3/SrTiO3. The orbital nature of an electron largely affects its spin-orbit interaction, which can be determined independently either from the weak-localization model in normal state or from the upper critical fields in superconducting state. We have developed a practical scheme to extract spin-orbit parameters from upper critical fields for low transition temperature superconducting systems with strong spin-orbit coupling. A striking discrepancy in the extracted spin-orbit coupling parameters was uncovered for the first time in high quality LaAlO3/SrTiO3 samples grown by oxide molecular beam epitaxy technique, indicating a difference in the spin-relaxation mechanism for the charge transport above and below the superconducting transition temperature. Such a finding supports for a possible orbital selectivity for the Cooper pairing and thus an electronic phase separation at the interface of LaAlO3/SrTiO3 that may shed some lights toward understanding the exotic low-density superconductivity. Those results were published in the new APS open access journal of Physical Review Research (PRR 2, 013311(2020)).

https://www.phys.sinica.edu.tw/files/bpic20200316035454pm_Fig_summary_PRR_ver2_內文附圖.png

WebSite: https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.013311

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