Angular magnetoresistance in the (DMET-TSeP)2X family:: (X= AuCl2, AuI2):: Field-induced spin-density waves and commensurability effects

We present a detailed study of angular-dependent magnetoresistance (AMR) in a class of low-dimensional organic conductor (DMET-TSeF)(2)X, where X stands for X = AuCl2 and AuI2. The angular-dependent background magnetoresistance for both compounds reveals a local minimum at the angle where the field-induced spin-density wave (FISDW) at lowest field is observed, contrary to the standard quasi-one-dimensional systems like the Bechgaard salts. Both systems show commensurability effects of electron motion, reflected as a series of magnetoresistance dips in tilted magnetic field at Lebed magic angles. While commensurability effects in AuCl2 dominate the FISDW, AuI2 shows complicated AMR structure dominated by FISDW. These data indicate continuous sliding of the FISDW nesting Vector in the b-c plane.