Fermi surface dependence of the hall coefficient in the QUASI-2D molecular conductor /spl tau/-(P-S,S-DMEDT-TTF)/sub 2/(AuBr/sub 2/)/sub 1/(AuBr/sub 2/)/sub y/ (y=0.75)

Summary form only given. The planar donors in this tetragonal, layered structure molecular conductor do not stack but instead are arranged edge to edge along the a and b axes (|a|=|b|) to form a 2D conducting grid. Band structure calculations predict a dramatic change in FS topology near y = 0.75. We find that the temperature independent high temperature limit (T > 200 K) of the weak-field Hall coefficient and its qualitative temperature dependence at lower temperatures are consistent with only one of the two possible Fermi surfaces. In addition, the pronounced temperature dependence of both the weak-field Hall coefficient and the in-plane resistivity between 10 K and 100 K can be understood in terms of the temperature dependence of the scattering path length and its anisotropy along the 2D Fermi surface. The steady rise in resistivity below 10 K (down to 0.7 K) may be indicative of density-wave formation or localization.