Quantum oscillations reveal the low temperature Fermi surfaces of FeSe1−xSx tuned by chemical and applied pressure across the nematic phase transition*

We present the evolution of the Fermi surfaces and electronic interactions across the nematic phase transition in single crystals of FeSe1−xSx using Shubnikov-de Haas oscillations in high magnetic fields up to 45 tesla in the low temperature regime. We will compare the effect of the chemical and applied hydrostatic pressure on the low-energy electronic structure and discuss the role of Lifshitz transitions and the changes in electronic correlations across the nematic phase transition. Our results can shed light on the interplay between competing electronic orders in FeSe1−xSx which can be finely tuned by combing chemical and applied pressure.