# Site-Selective Antimony Doping in Arsenic Zigzag Chains of 112-type Ca1-xLaxFeAs2

## TL;DR

This study investigates how site-selective antimony doping in the arsenic zigzag chains of Ca1-xLaxFeAs2 influences its structure and superconducting properties, revealing doping preferences and structural effects on Tc enhancement.

## Contribution

It provides the first detailed analysis of site-specific Sb doping effects in 112-type iron-based superconductors, linking structural changes to Tc improvements.

## Key findings

- Sb prefers substitution in As zigzag chains, not in FeAs layers.
- Sb doping increases the superconducting transition temperature to 47 K.
- Structural analysis explains Tc enhancement due to Sb doping.

## Abstract

Single crystal X-ray diffraction studies were performed for the Sb-doped 112-type iron-based superconductor Ca1-xLaxFeAs2 with the superconducting transition temperature Tc of 47 K. Doped Sb preferably substituted not for As(1) in the FeAs layers but for As(2) in the layers of As zigzag chains. Structural reasons for Tc enhancement by Sb doping were discussed.