Pressure-Induced Superconductivity from Doping-Induced Antiferromagnetic Phase of 112-type Ca$_{1-x}$La$_{x}$FeAs$_{2}$

TL;DR

This study investigates how applying pressure suppresses antiferromagnetic order and induces superconductivity in La-doped CaFeAs2, revealing pressure as a key tuning parameter for phase transitions in this material.

Contribution

It demonstrates pressure-induced suppression of antiferromagnetism and emergence of superconductivity in 112-type Ca$_{1-x}$La$_{x}$FeAs$_{2}$, providing new insights into phase control via pressure.

Findings

Superconductivity appears at critical pressures of 1.5 and 3.4 GPa for specific doping levels.

Antiferromagnetic transition temperature decreases with pressure, with slopes of -15 and -2 K/GPa.

Pressure suppresses AFM phase and induces superconductivity in La-doped CaFeAs2.

Abstract

The effects of pressure on antiferromagnetic (AFM) and superconducting phase transitions of 112-type Ca$_{1-x}$La$_{x}$FeAs$_{2}$ were studied, and the in-plane electrical resistivity $\rho_{ab}$ was measured with an indenter-type pressure cell. The AFM phase transition temperatures of $T_{\rm N}$ = 47, 63, and 63 K at ambient pressure for $x$ = 0.18, 0.21, and 0.26 was suppressed by applying pressure $P$, with superconductivity emerging at critical pressures of $P_{\rm c}$ $\simeq$ 0, 1.5, and 3.4 GPa, respectively. Correspondingly, the slope of $T_{\rm N}$ against $P$ decreased as $dT_{\rm N}/P$ $\simeq$ $-$15 and $-$2 K/GPa for $x$ = 0.21 and 0.26, respectively. Thus, although the AFM phase was stabilized with La doping $x$, the AFM phase was suppressed by pressure, and superconductivity eventually emerged.