Magnetotransport study of α-Me2Et2N[Ni(dmit)2]2 and related materials

Magnetoresistance of organic conductor, α-Me2Me2N[Ni(dmit)2]2, was measured for the magnetic field along a∗-axis. We found four different types of closed orbits (α-, β-, γ-, σ) through Shubnikov-de Haas (SdH) oscillation. The areas of these four closed orbits are estimated to be 0.23%, 4.6%, 87.4%, 11.3% of first Brillouin zone, respectively. The results are consistent with the band structure recently derived from the crystal structure at 11K. Contrary to α-Me2Et2N[Ni(dmit)2]2, α-C7H16N[Ni(dmit)2]2 shows neither angular dependent magnetoresistance oscillation nor SdH oscillation for the magnetic field up to 8 T.