paper

Coexistence of superconductivity and antiferromagentic order in Er $_{2}$ O $_{2}$ Bi with anti-ThCr $_{2}$ Si $_{2}$ structure

arXiv:2105.06642

Abstract

We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er $_{2}$ O $_{2}$ Bi with anti-ThCr $_{2}$ Si $_{2}$ -type structure through resistivity, magnetization, specific heat measurements and first-principle calculations. The superconducting transition temperature $T_{c}$ of 1.23 K and antiferromagnetic transition temperature $T_{N}$ of 3 K are observed in the sample with the best nominal composition. The superconducting upper critical field $H_{c2}$ (0) and electron-phonon coupling constant $I^»$ $_{e - p h}$ in Er $_{2}$ O $_{2}$ Bi are similar to those in the previously reported non-magnetic superconductor Y $_{2}$ O $_{2}$ Bi with the same structure, indicating that the superconductivity in Er $_{2}$ O $_{2}$ Bi may have the same origin as in Y $_{2}$ O $_{2}$ Bi. The first-principle calculations of Er $_{2}$ O $_{2}$ Bi show that the Fermi surface is mainly composed of the Bi 6 $p$ orbitals both in the paramagnetic and antiferromagnetic state, implying minor effect of the 4 $f$ electrons on the Fermi surface. Besides, upon increasing the oxygen incorporation in Er $_{2}$ O $_{x}$ Bi, $T_{c}$ increases from 1 to 1.23 K and $T_{N}$ decreases slightly from 3 to 2.96 K, revealing that superconductivity and antiferromagnetic order may compete with each other. The Hall effect measurements indicate that hole-type carrier density indeed increases with increasing oxygen content, which may account for the variations of $T_{c}$ and $T_{N}$ with different oxygen content.

Coexistence of superconductivity and antiferromagentic order in Er2​O2​Bi with anti-ThCr2​Si2​ structure

Abstract

Coexistence of superconductivity and antiferromagentic order in Er $_{2}$ O $_{2}$ Bi with anti-ThCr $_{2}$ Si $_{2}$ structure