Thermoelectric power of Ba(Fe_1−xCo_x)₂As₂(0 ≤ x ≤ 0.05) and Ba(Fe_1−xRh_x)₂As₂(0 ≤ x ≤ 0.171)

Abstract

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