
%0 Journal Article
%A Bennett, JC 
%A Boswell, FW 
%A Prodan, A 
%A Corbett, JM 
%A Ritchie, S 
%T The Effects of Transition Metal Substitutions in the NbTe<sub>4</sub>-TaTe<sub>4</sub> Charge-Density Wave System
%J Australian Journal of Chemistry
%D 1992/09/01
%V 45
%N 9
%P 1363-1374
%K 
%R https://doi.org/10.1071/CH9921363
%U https://www.publish.csiro.au/paper/CH9921363 
%X At room temperature, the structures of TaTe4 and NbTe4 are modulated by the presence of a charge-density wave which in the former compound is commensurate with the parent lattice and in the latter incommensurate. In addition, a series of incommensurate mixed crystals ( Tal-xNbx )Te4 (0 &#8804; x &#8804;) exist in which the modulation wavevector increases as a function of x. In this paper, we report the occurrence of a systematic variation in the period of the charge-density wave upon substitution of the transition metal elements Ti, Zr or V for either Nb or Ta. Electron diffraction experiments reveal that, in TaTe4, substitutions of Group 4 elements Ti and Zr result in an incommensurate modulation with a decrease in the modulation wavevector q. In NbTe4, substitutions of Ti or Zr also reduce q, in this case towards the commensurate value, and, at sufficiently high concentrations, a commensurate phase is stabilized at room temperature. Vanadium substitutions in NbTe4 result in a slight increase in q. Satellite dark-field images reveal the presence of defects in the modulation structures of the doped crystals. The above results are discussed in terms of the factors which determine the charge-density wave periodicity in the NbTe4-TaTe4 system. 
