Thermoelectric power of Ba(Fe1-xRux)2As2 and Ba(Fe1-xCox)2As2: possible changes of Fermi surface with and without changes in electron count

TL;DR

This study investigates how thermoelectric power varies with doping in Ba(Fe1-xRux)2As2 and Ba(Fe1-xCox)2As2, revealing changes in electronic structure and correlations near specific doping levels, and compares these effects across different dopants.

Contribution

It provides new insights into the evolution of electronic properties with doping in iron-based superconductors, highlighting possible Fermi surface changes without altering electron count.

Findings

Significant electronic structure changes near 7% and 30% Ru-doping.

Confirmed the existing x-T phase diagram for Ba(Fe1-xRux)2As2.

Compared thermoelectric power evolution between Ru and Co doping series.

Abstract

Temperature-dependent, in-plane, thermoelectric power (TEP) data are presented for Ba(Fe1-xRux)2As2 (0 < x < 0.36) single crystals. The previously outlined x - T phase diagram for this system is confirmed. The analysis of TEP evolution with Ru-doping suggests significant changes in the electronic structure, correlations and/or scattering occurring near ~7% and ~30% of Ru-doping levels. These results are compared with an extended set of TEP data for the electron-doped Ba(Fe1-xCox)2As2 series.