Reemergence of high-T<sub>c</sub> superconductivity in the (Li<sub>1-x</sub>Fe <sub>x</sub> )OHFe<sub>1-y</sub>Se under high pressure.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29371605.
- Also identified by DOI 10.1038/s41467-018-02843-7 and PMC identifier 5785538.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
In order to elucidate pressure-induced second superconducting phase (SC-II) in A <sub>x</sub> Fe<sub>2-y</sub>Se<sub>2</sub> (A = K, Rb, Cs, and Tl) having an intrinsic phase separation, we perform a detailed high-pressure magnetotransport study on the isoelectronic, phase-pure (Li<sub>1-x</sub>Fe <sub>x</sub> )OHFe<sub>1-y</sub>Se single crystals. Here we show that its ambient-pressure superconducting phase (SC-I) with a critical temperature T<sub>c</sub> ≈ 40 K is suppressed gradually to below 2 K and an SC-II phase emerges above P<sub>c</sub> ≈ 5 GPa with T<sub>c</sub> increasing progressively to above 50 K up to 12.5 GPa. Our high-precision resistivity data uncover a sharp transition of the normal state from Fermi liquid for SC-I to non-Fermi liquid for SC-II phase. In addition, the reemergence of high-T<sub>c</sub> SC-II is found to accompany with a concurrent enhancement of electron carrier density. Without structural transition below 10 GPa, the observed SC-II with enhanced carrier density should be ascribed to an electronic origin presumably associated with pressure-induced Fermi surface reconstruction.