Reconstruction of the Fermi surface induced by high magnetic field in the quasi-two-dimensional charge density wave conductor η−Mo4O11

Abstract

Low-dimensional charge density wave (CDW) systems, which undergo successive so-called Peierls phase transitions at characteristic temperatures associated with corresponding changes in electronic structure, are of great importance for exploring novel quantum physics. Here, we report systematic research of the magnetotransport properties for the quasi-two-dimensional CDW conductor $\ensuremath{\eta}\text{\ensuremath{-}}\mathrm{M}{\mathrm{o}}_{4}{\mathrm{O}}_{11}$ under high magnetic fields up to 59 T. Measurements of in-plane and out-of-plane magnetoresistance and Hall resistance have been carried out to determine the Fermi surface (FS) structure at low temperatures and high magnetic fields. Beyond the quantum limit (QL), fast quantum oscillations (QOs) with complex periods have been found in both MR and Hall resistance, representing a direct measurement of the area of the FS. In addition, we observe a conspicuous phase transition at 45 T. The QO frequency and carrier density successively increase above the QL and phase transition fields. Consequently, we propose that such remarkable feature of the magnetic field dependence of the fast QOs for $\ensuremath{\eta}\text{\ensuremath{-}}\mathrm{M}{\mathrm{o}}_{4}{\mathrm{O}}_{11}$ arises from the field-induced density wave transition and FS reconstruction. We have further discussed the mechanism and provided the evolution on the geometry of the FS with magnetic field in the second CDW state based on the field-dependent FS model.