Nernst effect in single crystals of the pnictide superconductor CaFe1.92Co0.08As2 and parent compound CaFe2As2

We report a combined study of the Nernst coefficient (nu), Hall effect, and thermoelectric power of CaFe2As2 and CaFe1.92Co0.08As2 single crystals. The absolute value of nu in both samples is enhanced, probably due to ambipolar flow of electronlike and holelike quasiparticles. The onset of spin-density-wave (SDW) order in CaFe2As2 causes further rapid rise of the Nernst coefficient. On the contrary, in the CaFe1.92Co0.08As2 crystal we do not see any feature of nu(T), which could be clearly associated with SDW fluctuations. In this Co-doped sample there is also no noticeable increase in of nu in the vicinity of superconducting transition despite the expectation of such due to vortex movement.