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

TL;DR

This study investigates the thermoelectric and electronic transport properties of Fe{1+d}Te{1-x}Se{x} single crystals, revealing magnetic transition effects in the parent compound and superconducting behavior in doped samples, with insights into magnetic correlations.

Contribution

It provides new resistivity, Hall, Seebeck, and Nernst data for Fe{1+d}Te{1-x}Se{x} crystals, highlighting the effects of doping on magnetic and superconducting properties.

Findings

Magnetic transition at 61 K in parent compound Fe{1.04}Te.

Superconductivity observed at ~13.9 K in doped samples.

Divergence in properties below 80 K related to magnetic correlations.

Abstract

We report resistivity as well as the Hall, Seebeck and Nernst coefficients data for Fe{1+d}Te{1-x}Se{x} single crystals with x = 0, 0.38, and 0.40. In the parent compound Fe{1.04}Te we observe at Tn = 61 K a sudden change of all quantities studied, which can be ascribed to the Fermi surface reconstruction due to onset of the antiferromagnetic order. Two very closely doped samples: Fe{1.01}Te{0.62}Se{0.38} (Se38) and Fe{1.01}Te{0.60}Se{0.40} (Se40) are superconductors with Tc = 13.4 K and 13.9 K, respectively. There are no evident magnetic transitions in either Se38 or Se40. Properties of these two single crystals are almost identical at high temperatures, but start to diverge below T ~ 80 K. Perhaps we see the onset of scattering that might be a related to changes in short range magnetic correlations caused by selenium doping.