Electrodynamics of BaFe2As2 from infrared measurements under pressure

TL;DR

This study investigates how pressure influences the infrared optical properties of BaFe2As2, revealing a transition towards metallic behavior and highlighting that lattice changes alone do not fully explain the material's low-energy electrodynamics.

Contribution

It provides new insights into pressure-induced electronic changes in BaFe2As2, emphasizing the role of factors beyond lattice modifications in its electrodynamics.

Findings

Magnetic order-related mid-infrared absorption decreases with pressure

Drude component increases, indicating metallic transition

Spectral weight analysis shows complex pressure effects

Abstract

We report on an infrared study on the undoped compound BaFe2As2 as a function of both pressure (up to about 10 GPa) at three temperatures (300, 160, and 110 K). The evolution with pressure and temperature of the optical conductivity shows that, by increasing pressure, the mid-infrared absorptions associated with magnetic order are lowered while the Drude term increases, indicating the evolution towards a conventional metallic state. We evaluate the spectral weight dependence on pressure comparing it to that previously found upon doping. The whole optical results indicate that lattice modifications can not be recognized as the only parameter determining the low-energy electrodynamics in these compounds.