Exploration of metastable iron selenium-based superconductors
Abstract
<p indent="0mm">Intercalated iron selenium (FeSe)-based superconductors have emerged as a prominent subject of research in the field of condensed matter physics due to their high superconducting transition temperatures and unique Fermi surface topology, which exhibit distinct electron-pairing mechanisms compared to other iron-based superconductors. Owing to the lowest oxidation state of Fe being 2+, intercalation through conventional high-temperature methods inevitably leads to phase separation and formation of magnetic insulating phases with ordered Fe vacancies, hindering investigations into their intrinsic properties. To address this challenge, low-temperature intercalation methods such as the liquid ammonia, solvothermal, and hydrothermal methods, have been developed. These approaches have successfully synthesized a series of single-phase superconductors without Fe vacancies. Herein, we provide a comprehensive review of the design, development, and progress of intercalated FeSe superconductors and outline future research directions in this field.</p>
