Magnetothermoelectric effects in Fe$_{1+d}$Te$_{1-x}$Se$_x$

We report data on resistivity as well as Hall, Seebeck and Nernst coefficients for the Fe$_{1+d}$Te$_{1-x}$Se$_x$ single crystals with $x$ = 0, 0.39, and 0.40. The parent compound $\rm Fe_{1.04}Te$ exhibits a Fermi surface reconstruction at $T$ = 61 K, which is ascribed to the onset of the antiferromagnetic order. Two very closely doped samples: $Fe_{1.01}Se_{0.39}Te_{0.61}$ (Se39) and $\rm Fe_{1.01}Se_{0.4}Te_{0.6}$ (Se40) are superconductors with $T_c$ = 13.4 K and 13.9 K, respectively. Properties of these two single crystals are almost identical at high temperatures, but start to diverge below $T \approx$ 80 K. Despite there is no magnetic transition in neither Se39 nor Se40, the observed differences seem to be a consequence of varying with selenium content spin correlations.