Inducing a CDW ground state in Nb 3Se 4 by intercalation

Abstract

A charge-density-wave (CDW) ground state that exists in Nb 3Te 4 below 115 K is not observed in the isostructural and isoelectronic Nb 3Se 4 and Nb 3S 4. Intercalating indium into Nb 3Se 4 induces a Peierls transition to a CDW ground state near 35 K judging by a peak in the resistivity. The onset temperature of this resistance peak is influenced by the mole fraction intercalated. Electron diffraction (ED) evidence supports these findings. In contrast, intercalating Nb 3S 4 with indium does not produce a resistivity peak above ∼12 K to suggest the presence of a CDW ground state. An electron diffraction study has linked complex superlattice satellites (SLS) near 90 K in both chalcogenides to a CDW transition but the present resistivity results suggest that this is not the case. A number of other guests intercalated into either chalcogenide do not produce any resistivity features to suggest a Peierls transition. A CDW does, however, appear to exist in Ga 1.0Nb 3Te 4 and provides support for an apparent synergism between group III metals intercalated into Nb 3Te 4 and Nb 3Se 4 and the existence of a CDW ground state. Pulsed resistivity measurements of In 1.0Nb 3Se 4 at 12 K with fields to ∼20 V/cm indicate that the electrical transport remains ohmic.