Measurement and analysis of the Hall effect of A-Fe$_2$As$_2$ single crystals with A = Ba, Ca or Sr

TL;DR

This study measures the Hall coefficient in AFe$_2$As$_2$ single crystals with A = Ba, Ca, Sr, revealing insights into their electronic properties and estimating the spin density wave gaps, which are relevant for understanding high-temperature superconductivity.

Contribution

The paper provides the first detailed Hall effect measurements on AFe$_2$As$_2$ compounds and estimates their SDW gaps, linking transport data with quantum oscillation results.

Findings

Hall coefficient of Sr-122 aligns with quantum oscillation data.

Estimated SDW gap for Sr-122 is 710±70 K.

Estimated SDW gap for Ba-122 is 435±20 K.

Abstract

We report measurements of the Hall coefficient $R_H$ for single crystals of AFe$_2$As$_2$ with $A = Ba, Ca$ or $Sr$ which are the anti-ferromagnetic parent compounds of some high temperature pnictide superconductors. We show that $R_H$ of Sr-122 is consistent with high field quantum oscillation data. Our $R_H(T)$ data can also be used to estimate values of the spin density wave gap, giving $\Delta_{SDW}(0) = 710\pm 70$ K for Sr-122 and $435\pm 20$ K for Ba-122.