Thermoelectric power of Ba(Fe1-xCox)2As2, 0\leqx\leq0.05, and Ba(Fe1-xRhx)2As2, (0\leqx\leq0.171)

TL;DR

This study measures the temperature-dependent thermoelectric power in Ba(Fe1-xCox)2As2 and Ba(Fe1-xRhx)2As2 single crystals, revealing a gradual Lifshitz transition and confirming phase diagrams with new detailed data.

Contribution

It provides new thermoelectric power measurements across specific doping ranges, revealing a gradual Lifshitz transition and confirming phase diagrams for these iron-based superconductors.

Findings

Evidence of a Lifshitz transition with gradual evolution in thermoelectric power.

Similar thermoelectric behavior observed in Co and Rh substituted systems.

Confirmation of existing phase diagrams through thermoelectric power data.

Abstract

Temperature-dependent, in-plane, thermoelectric power data are presented for single crystals of Ba(Fe1-xCox)2As2, 0\leqx\leq0.05, and Ba(Fe1-xRhx)2As2, (0\leqx\leq0.171). Given that previous thermoelectric power and angle resolved photoemission spectroscopy studies of Ba(Fe1-xCox)2As2 delineated a rather large Co-concentration range for Lifshitz transitions to occur, and the underdoped side of the phase diagram is poorly explored, new measurements of thermoelectric power on tightly spaced concentrations of Co, 0\leqx\leq0.05, were carried out. The data suggest evidence of a Lifshitz transition, but instead of a discontinuous jump in thermoelectric power between 0\leqx\leq0.05, a more gradual evolution in the S(T) plots as x is increased was observed. The thermoelectric power data of Ba(Fe1-xRhx)2As2 show very similar behavior to that of Co substituted BaFe2As2. The previously outlined T - x phase diagrams for both systems are further confirmed by these thermoelectric power data.