Systematics of the temperature-dependent inter-plane resistivity in Ba(Fe$_{1-x}$T$_x$)$_2$As$_2$ with T= Rh, Ni, and Pd

TL;DR

This study systematically investigates how transition metal substitutions (Ni, Pd, Rh) affect the inter-plane resistivity and pseudogap behavior in Ba(Fe$_{1-x}$T$_x$)$_2$As$_2$ superconductors, revealing differences in pseudogap suppression and Fermi surface gapping.

Contribution

It provides a comparative analysis of resistivity and pseudogap features across different dopants, highlighting the variation in Fermi surface gapping and pseudogap suppression.

Findings

Resistivity crossover at a characteristic pseudogap temperature $T^*$ from non-metallic to metallic behavior.

Suppression of $T^*$ is faster for Ni and Pd doping than for Co and Rh.

High doping levels in Co and Rh cases show an additional resistivity minimum when superconductivity is suppressed.

Abstract

Temperature-dependent inter-plane resistivity, $\rho_c(T)$, was measured systematically as a function of transition metal substitution in the iron-arsenide superconductors Ba(Fe$_{1-x}$T$_x$)$_2$As$_2$, $T$= Ni, Pd, Rh. The data are compared with the behavior found in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$, revealing resistive signatures of pseudogap. In all compounds we find resistivity crossover at a characteristic pseudogap temperature $T^*$ from non-metallic to metallic temperature dependence on cooling. Suppression of $T^*$ proceeds very similar in cases of Ni and Pd doping and much faster than in similar cases of Co and Rh doping. In cases of Co and Rh doping an additional minimum in the temperature-dependent $\rho_c$ emerges for high dopings, when superconductivity is completely suppressed. These features are consistent with the existence of a charge gap covering part of the Fermi surface. The part of the Fermi surface affected by this gap is notably larger for Ni and Pd doped compositions than in Co and Rh doped compounds.