Anisotropies in the magnetotransport properties of quasi-two-dimensional eta-Mo4O11 crystals

Magnetotransport measurements have been made for quasi-two-dimensional eta- Mo4O11 crystals in its charge-density-wave (CDW) phases along the crystallo graphic a*-, b-, and c-axes at low temperatures 0.3-4.2 K in magnetic field s up to 11 T. The diagonal components rho(xx) (or b-axis), rho(yy) (c-axis) , and rho(zz) (a*-axis) of the resistivity tensor are highly anisotropic (r ho(xx) < rho(yy) much less than rho(zz); rho(zz)/rho(xx) similar to 10(2)). Computer simulations for the magnetic field dependence of rho(xx), rho(yy) , and rho(xy) are made using a multicarrier model, in good agreement with t he observations. From the in-plane anisotropy, we have estimated the anisot ropic shape of the Fermi surfaces. These anisotropic properties are discuss ed by considering the characteristic crystal structure and conduction proce ss via conducting and insulating layers along the z-axis. Furthermore, in v iew of the existing band model of this material and the data analyses, the observed quantum oscillations are not simply due to Shubnikov de-Haas oscil lations but to some magnetic-field induced phase transition, as found for l ow-dimensional organic Bechgaard salts; the essence of which is the presenc e of hidden quasi-one-dimensional Fermi surface.