Development and low-temperature crystal structures of M(dmiX)2(X=S,Se) conductors

The low-temperature crystal structures of α-[(CH3)2(C2H5)2N][Ni(dmit)2]2(11 K), (C7H16N)[Ni(dmit)2]2(20 K) and γ-[(CH3)2(C2H5)2N][Ni(dmit)2]2(4.3 K) were determined by use of new imaging plate(IP) system equipped with He refrigerator; γ-[(CH3)2(C2H5)2N][Ni(dmit)2]2 was found to be metallic down to 2K with the Pauli-like magnetic susceptibility and to have the round 2D Fermi surfaces at 4.3 K. [(CH3)3NH][NI(dmise)2]2 and [(CH3)2H2N][Ni(dmit)2]2 gave 3D Fermi surfaces owing to the strong intersheet interactions between their selenone groups.