CHARGE-DENSITY WAVES AND DENSITY-OF-STATES IN THE INTERCALATED TUNNELSTRUCTURE TLXNB3TE4

Tunnel structures, into which a variety of atoms can be intercalated, offer a promising approach for investigation of the interaction betwee n charge-density waves (CDW's) and foreign atoms. For this purpose sin gle crystals of TlxNb3Te4 with 0 less than or equal to x less than or equal to 1 were prepared, CDW's were observed below room temperature f or all crystals, despite the wide range of Tl content. The wave vector s were determined by electron diffraction and the transition temperatu res by resistivity measurements. For x < 0.25 the transition temperatu res were less than those of the pure material, while for x > 0.25 both the transition temperatures and wave vectors increased strongly and p assed through a maximum near x = 0.75. The results were interpreted in terms of the crystal structure and the variation of the electron dens ity of states at the Fermi level, as additional electrons were contrib uted to the host crystal with increasing Tl content. This is an exampl e of a quasi-one-dimensional, inorganic system in which the transition temperature and CDW vector can be conveniently tuned by adjustments o f the intercalate content.