Charge density waves in Nb3Te4: Effects of indium and thallium intercalation

High quality single crystals of InyNb3Te4 and TlyNb3Te4 up to several mm long have been prepared for the first time by metal vapor intercalation into pure Nb3Te4 crystals. Using electron diffraction it was shown that the CDW transition temperature was sharply increased for both intercalated compounds. Wave vectors in both became incommensurate and increased by up to 10%. The harmonic CDWs in Nb3Te4 became anharmonic for InyNb3Te4 and even more so for TlyNb3Te4. Diffraction effects attributed to ordering of the intercalate in the tunnels were observed for InyNb3Te4. It has been demonstrated that the In and Tl intercalated Nb3Te4 system offers a unique opportunity to investigate the influence of adjacent ionic intercalate rows on the characteristics of CDWs along the Nb chains.