Fermi surface properties of the bifunctional organic metal κ-(BETS)2Mn[N(CN)2]3 near the metal-insulator transition

We present detailed studies of the high-field magnetoresistance of the layered organic metal κ-(BETS)2Mn- [N(CN)2]3 under a pressure slightly above the insulator-metal transition. The experimental data are analyzed in terms of the Fermi surface properties and compared with the results of first-principles band structure calculations. The calculated size and shape of the in-plane Fermi surface are in very good agreement with those derived from Shubnikov-de Haas oscillations as well as the classical angle-dependent magnetoresistance oscillations. A comparison of the experimentally obtained effective cyclotron masses with the calculated band masses reveals electron correlations significantly dependent on the electron momentum. The momentum- or band-dependent mobility is also reflected in the behavior of the classical magnetoresistance anisotropy in a magnetic field parallel to layers. Other characteristics of the conducting system related to interlayer charge transfer and scattering mechanisms are discussed based on the experimental data. Besides the known high-field effects associated with the Fermi surface geometry, new pronounced features have been found in the angle-dependent magnetoresistance, which might be caused by coupling of the metallic charge transport to a magnetic instability in proximity to the metal-insulator phase boundary.We are grateful to N.D. Kushch for providing the high-quality crystals for our studies and to P.D. Grigoriev for numerous useful discussions. The work was supported by the German Research Foundation (DFG) via the Grant No. KA 1652/4-1. The high-field measurements were done under support of the LNCMI-CNRS, member of the European Magnetic Field Laboratory (EMFL). V.N.Z. acknowledges the support from RFBR Grant No. 18-02-00280. Work in Spain was supported by the Spanish Ministerio de Economa y Competitividad (Grants No. FIS2015-64886-C5-4-P and No. CTQ2015-64579-C3-3-P) and Generalitat de Catalunya (2017SGR1506, 2017SGR1289, and XRQTC). E.C. acknowledges support from the Severo Ochoa Centers of Excellence Program under Grant No. SEV-2015-0496. P.A. acknowledges support from the Maria de Maeztu Units of Excellence Program under Grant No. MDM-2017-0767.Peer reviewe