Combined resistivity and Hall effect study on NaFe$_{1-x}$Rh$_x$As single crystals

TL;DR

This study investigates the electrical transport properties of Rh-doped NaFeAs superconductors, revealing two crossover regions related to structural and nematic fluctuations through resistivity and Hall effect measurements.

Contribution

It provides new insights into the scattering rate, effective mass, and charge carrier density changes in Rh-doped NaFeAs, linking them to structural and nematic phase transitions.

Findings

Identification of two crossover regions in resistivity and Hall data.

Correlation of the first crossover with structural transition.

Association of the second crossover with nematic fluctuations.

Abstract

Electrical transport measurements are used to study the Rh-doped NaFeAs superconductor series with a focus on the tetragonal phase. The resistivity curvature has an anomalous temperature dependence evidencing in the phase diagram two crossover regions of changes in the scattering rate, the effective mass as well as of the charge carrier density. The first crossover region is directly connected to the structural transition and resembles the onset of resistivity anisotropy. The second crossover region can as well be deduced from the temperature dependent Hall coefficient. A comparison to literature NMR data suggests this region to be connected with nematic fluctuations far above the tetragonal to orthorhombic phase transition.