Manifestation of the spin textures in the thermopower of MnSi

Abstract

To identify possible spin texture contributions to thermoelectric transport, we present a detailed temperature and pressure dependence of thermopower S in MnSi, as well as a low-temperature study of S in a magnetic field. We find that S/T reconstructs the phase diagram of MnSi encompassing the Fermi liquid, partially ordered, and non–Fermi-liquid phases. Our results indicate that the latter two phases have essentially the same nature. In the partially ordered phase, S(T) is strongly enhanced, which may be understood as a spiral-fluctuation–driven phase. A low-temperature upturn in S/T pertaining to the partial-order phase persists up to the highest pressure, 24 kbar. Contrarily, a small suppression of S(T) is observed in the ordered skyrmion lattice A phase.