Understanding doping, vacancy, lattice stability and superconductivity in KxFe2-ySe2

TL;DR

This paper uses first-principles calculations to clarify the roles of vacancies, doping, and lattice stability in the superconductivity of KxFe2-ySe2, addressing key controversies in the field.

Contribution

It provides new insights into the effects of doping and vacancies on the phase responsible for superconductivity in KxFe2-ySe2.

Findings

Identified the phase responsible for superconductivity.

Revealed the impact of doping on lattice stability.

Clarified the role of Fe vacancies in superconductivity.

Abstract

Metal-intercalated iron selenides are a class of superconductors that have received much attention but are less understood in comparison with their FeAs-based counterparts. Here, the controversial issues such as Fe vacancy, the real phase responsible for superconductivity, and lattice stability have been addressed based on first-principles calculations. New insights into the distinct features in terms of carrier doping have been revealed.