Fermi Surface and Band Structure of (Ca,La)FeAs2 Superconductor from Angle-Resolved Photoemission Spectroscopy

TL;DR

This study investigates the electronic structure of the (Ca,La)FeAs2 superconductor using band structure calculations and ARPES, revealing multiple hole and electron bands crucial for understanding its superconductivity.

Contribution

It provides detailed experimental and theoretical electronic band structures of (Ca,La)FeAs2, a superconductor with a unique layer structure, advancing knowledge of iron-based superconductors.

Findings

Identification of four hole-like bands around Gamma

Observation of one electron-like Fermi surface near M

Comparison with other iron-based superconductors

Abstract

The (Ca,R)FeAs2 (R=La,Pr and etc.) superconductors with a signature of superconductivity transition above 40 K possess a new kind of block layers that consist of zig-zag As chains. In this paper, we report the electronic structure of the new (Ca,La)FeAs2 superconductor investigated by both band structure calculations and high resolution angle-resolved photoemission spectroscopy measurements. Band structure calculations indicate that there are four hole-like bands around the zone center $\Gamma$(0,0) and two electron-like bands near the zone corner M(pi,pi) in CaFeAs2. In our angle-resolved photoemission measurements on (Ca0.9La0.1})FeAs2, we have observed three hole-like bands around the Gamma point and one electron-like Fermi surface near the M(pi,pi) point. These results provide important information to compare and contrast with the electronic structure of other iron-based compounds in understanding the superconductivity mechanism in the iron-based superconductors.