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 $(p,T)$ 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.