Evidence for the complicated Fermi surface in 2H-and 4H-NbSe2

摘要

In this study, we have found superconducting state (SC) at 7.4 and 6.4 K and charge density wave state (CDW) at 35 and 42 K in our 2H- and 4H-NbSe2 single crystals, respectively. Besides this, there exists a positive magneto-resistance (MR) below the CDW transition temperature on both the crystals. Therefore, we have calculated their fractional change in MR i.e., Delta rho/rho (0) around 8 K in H (aSyen) plane of NbSe2 and H (||) plane of NbSe2 configurations. Both single crystals show anisotropic Delta rho/rho (0), which are described by Kohler's rule, two-band model and magnetic breakdown model. In the present scenario, the magnetic breakdown model explains our anisotropic Delta rho/rho (0) better than other two models: Kohler's and two-band model. This model also established the presence of complicated Fermi surface on both single crystals.