Electron-hole Asymmetry and Quantum Critical Point in Hole-doped BaFe$_2$As$_2$

TL;DR

This study uses first-principles calculations to reveal fundamental differences between hole-doped and electron-doped BaFe2As2, highlighting a unique quantum critical point and orbital ordering in the hole-doped case.

Contribution

It uncovers the distinct electronic and magnetic behaviors in hole-doped BaFe2As2, including orbital-selective ordering and a different quantum critical point mechanism.

Findings

Hole-doped side exhibits orbital-selective partial orbital ordering.

A unique SDW-to-AF quantum critical point is identified in hole-doped BaFe2As2.

Superconductivity appears near the quantum critical point in both doping types.

Abstract

We show, from first-principles calculations, that the hole-doped side of FeAs-based compounds is different from its electron-doped counterparts. The electron side is characterized as Fermi surface nesting, and SDW-to-NM quantum critical point (QCP) is realized by doping. For the hole-doped side, on the other hand, orbital-selective partial orbital ordering develops together with checkboard antiferromagnetic (AF) ordering without lattice distortion. A unique SDW-to-AF QCP is achieved, and $J_2$=$J_1/2$ criteria (in the approximate $J_1&J_2$ model) is satisfied. The observed superconductivity is located in the vicinity of QCP for both sides.