Charge density wave instabilities in the quasi-two-dimensional metal η-Mo4O11

Electrical resistivity, thermopower and specific heat have been measured on single crystals of monoclinic eta -Mo 4 O 11 grown by vapour phase transport. The anisotropy of the electrical resistivity establishes that eta -Mo 4 O 11 is a quasi-two-dimensional metal. All the physical properties show that two phase transitions take place at T c1 =109K and T c2 =30K. The authors propose that these transitions are due to charge density wave instabilities.