Pressure-induced Lifshitz transition in FeSe0.88S0.12 probed via 77Se-NMR.

Recently, FeSe1-xSx systems have received much attention because of the unique pressure-temperature phase diagram. We performed 77Se-NMR measurements on a single crystal of FeSe0.88S0.12 to investigate its microscopic properties. The shift of 77Se spectra exhibits anomalous enhancement at 1.0 GPa, suggesting a topological change in the Fermi surfaces, the so-called Lifshitz transition, occurs at 1.0 GPa. The magnetic uctuation simultaneously changes its properties, which implies a change in the dominant nesting vector. [ABSTRACT FROM AUTHOR]