Influence of Dirac Fermions on Magnetothermoelectric Transport in Iron-Based Superconductors

Abstract

AbstractWe report the Nernst coefficient (\(\nu \)) measurements in parent compounds of the iron pnictides \(\mathrm {CaFe_2As_2}\) and \(\mathrm {EuFe_2As_2}\) (“122”,) as well as the iron chalcogenide \(\mathrm {Fe_{1.04}Te}\) (“11”). In all three single crystals we observe an anomaly in \(\nu (T)\) that develops in the magnetically ordered state. However, there are clear differences between anomalies in the “122” iron pnictides and the “11” chalcogenide, which can be ascribed to presence of Dirac cones in the antiferromagnetic metallic state of “122” compounds. We also investigate influence of substitution of Fe with Co on the Nernst effect in the series of \(\mathrm {Eu(Fe_{1-x}Co_x)_2As_2}\) single crystals. We notice that even small cobalt doping (x = 0.15) causes eradication of Dirac fermions contribution to transport effects.KeywordsTopological InsulatorDirac FermionDirac ConeAnomalous ContributionIron PnictidesThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.