Structural, Magnetic and Electronic Properties of the Iron-Chalcogenide A$_x$Fe$_{2-y}$Se$_2$ (A=K, Cs, Rb, Tl and etc.) Superconductors

TL;DR

This paper reviews the structural, magnetic, and electronic properties of A$_x$Fe$_{2-y}$Se$_2$ superconductors, highlighting their unique features like Fe-vacancy order, magnetic structures, and electronic structures distinct from other Fe-based superconductors.

Contribution

It provides a comprehensive review of the recent findings on the structural, magnetic, and electronic properties of A$_x$Fe$_{2-y}$Se$_2$ superconductors, emphasizing their unique characteristics.

Findings

Distinct electronic structures from other Fe-based superconductors

Presence of Fe-vacancy order and magnetic structures

Discussion on superconducting gap and future perspectives

Abstract

The latest discovery of a new iron-chalcogenide superconductor A$_x$Fe$_{2-y}$Se$_2$(A=K, Cs, Rb, Tl and etc.) has attracted much attention due to a number of its unique characteristics, such as the possible insulating state of the parent compound, the existence of Fe-vacancy and its ordering, a new form of magnetic structure and its interplay with superconductivity, and the peculiar electronic structures that are distinct from other Fe-based superconductors. In this paper, we present a brief review on the structural, magnetic and electronic properties of this new superconductor, with an emphasis on the electronic structure and superconducting gap. Issues and future perspectives are discussed at the end of the paper.