FeSebaserade

FeSebaserade is the Swedish term used to describe FeSe-based materials, a subset of iron-based superconductors whose essential building block is a two-dimensional iron-selenium layer. In this nomenclature, the FeSe layer serves as the core structural motif, often modified by intercalation, doping, or substrate interactions to tune electronic properties. The parent compound FeSe crystallizes in a tetragonal PbO-type structure with iron forming a square lattice flanked by selenium atoms.

At ambient pressure, FeSe becomes superconducting below about 8 kelvin. Its superconductivity can be substantially enhanced by chemical or physical means, including intercalation of spacer layers, electron doping, or applying pressure. Intercalated FeSe compounds, in which spacer layers separate FeSe sheets, exhibit higher Tc values in the tens of kelvin range. In ultrathin forms, notably a monolayer of FeSe grown on SrTiO3, spectroscopic studies have reported onset temperatures well above 60 K, with transport measurements sometimes indicating lower effective Tc; the precise mechanism behind such enhancements remains under active investigation.

Researchers study the interplay between structural, electronic, and magnetic properties in FeSebaserade systems, including nematic order, spin fluctuations, and their evolution with doping and strain. Proposed explanations for high Tc in these materials involve modifications to the Fermi surface, correlation effects, and potential interfacial phonon coupling in monolayer configurations. The field continues to explore how these factors contribute to superconductivity and whether insights gained from FeSebaserade systems can guide the design of higher-Tc iron-based superconductors.

Applications of FeSebaserade materials are primarily experimental and research-oriented at present, limited by stability, phase separation tendencies, and the need for specialized synthesis or substrates. They remain a focal point for understanding unconventional superconductivity in iron-based systems.