Thermoelectric power and Hall coefficient measurements on Ba(Fe1-xTx)(2)As-2 (T=Co and Cu)

TitleThermoelectric power and Hall coefficient measurements on Ba(Fe1-xTx)(2)As-2 (T=Co and Cu)
Publication TypeJournal Article
Year of Publication2009
AuthorsMun ED, Bud'ko SL, Ni N, Thaler AN, Canfield PC
Journal TitlePhysical Review B
Volume80
Pages054517
Date Published08/01
ISBN Number1098-0121
Accession NumberISI:000269638500074
Keywordsband structure, barium compounds, cobalt compounds, copper compounds, doping, fermi surface, hall effect, high-temperature superconductors, iron compounds, metals, solid-state phase transformations, superconductivity, thermoelectric power
Abstract

Temperature-dependent thermoelectric power (TEP) data on Ba(Fe1-xTMx)(2)As-2 (TM=Co and Cu), complemented by the Hall coefficient data on the samples from the same batches, have been measured. For Co doping we clearly see a change in the temperature-dependent TEP and Hall coefficient data when the sample is doped to sufficient e (the number of extra electrons associated with the TM doping) so as to stabilize low-temperature superconductivity. Remarkably, a similar change is found in the Cu-doped samples at comparable e value, even though these compounds do not superconduct. These changes possibly point to a significant modification of the Fermi surface/band structure of Ba(Fe1-xTMx)(2)As-2 at small electron doping, that in the case of Co doping is just before, and probably allows for, the onset of superconductivity. These data further suggest that suppression of the structural/magnetic phase transition and the establishment of a proper e value are each necessary but, individually, not sufficient conditions for superconductivity.

URL<Go to ISI>://000269638500074
DOI10.1103/Physrevb.80.054517