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

Abstract

We present a detailed study of angular-dependent magnetoresistance (AMR) in a class of low-dimensional organic conductor $(\mathrm{D}\mathrm{M}\mathrm{E}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{S}\mathrm{e}\mathrm{F}{)}_{2}X,$ where X stands for $X={\mathrm{AuCl}}_{2}$ and ${\mathrm{AuI}}_{2}.$ 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 ${\mathrm{AuCl}}_{2}$ dominate the FISDW, ${\mathrm{AuI}}_{2}$ shows complicated AMR structure dominated by FISDW. These data indicate continuous sliding of the FISDW nesting vector in the $b\ensuremath{-}c$ plane.