Stabilization of NbTe3, VTe3, and TiTe3 via Nanotube Encapsulation

TL;DR

This study demonstrates the synthesis of previously unstable NbTe3, VTe3, and TiTe3 MX3 transition metal trichalcogenides in few- to single-chain form using nanotube encapsulation, revealing unique structural and electronic properties.

Contribution

It introduces a novel nano-confined growth method to stabilize and synthesize new MX3 materials that are unstable in bulk form, expanding the family of 1D transition metal chalcogenides.

Findings

Successful synthesis of NbTe3, VTe3, TiTe3 in few- to single-chain form

Observation of unique structural behaviors like spiraling and rocking distortion

DFT calculations elucidate stability and electronic structure

Abstract

The structure of MX3 transition metal trichalcogenides (TMTs, with M a transition metal and X a chalcogen) is typified by one-dimensional (1D) chains weakly bound together via van der Waals interactions. This structural motif is common across a range of M and X atoms (e.g. NbSe3, HfTe3, TaS3), but not all M and X combinations are stable. We report here that three new members of the MX3 family which are not stable in bulk, specifically NbTe3, VTe3, and TiTe3, can be synthesized in the few- to single-chain limit via nano-confined growth within the stabilizing cavity of multi-walled carbon nanotubes. Transmission electron microscopy (TEM) and atomic-resolution scanning transmission electron microscopy (STEM) reveal the chain-like nature and the detailed atomic structure. The synthesized materials exhibit behavior unique to few-chain quasi-1D structures, such as multi-chain spiraling and a trigonal anti-prismatic rocking distortion in the single-chain limit. Density functional theory (DFT) calculations provide insight into the crystal structure and stability of the materials, as well as their electronic structure.