Torsional instability in the single-chain limit of a transition metal trichalcogenide

TL;DR

This study synthesizes isolated single chains of NbSe3, revealing unique torsional waves and instability driven by charge transfer, with potential implications for nanoscale electronic properties.

Contribution

It demonstrates the synthesis and encapsulation of single-chain NbSe3, uncovering torsional instabilities not observed in bulk materials.

Findings

Observation of static and dynamic torsional waves in single chains

Charge transfer induces torsional wave instability

Encapsulation allows unhindered chain dynamics

Abstract

We report the synthesis of the quasi-one-dimensional transition metal trichalcogenide NbSe3 in the few chain limit, including the realization of isolated single chains. The chains are encapsulated in protective boron nitride or carbon nanotube sheaths to prevent oxidation and to facilitate characterization. Transmission electron microscopy reveals static and dynamic structural torsional waves not found in bulk NbSe3 crystals. Electronic structure calculations indicate that charge transfer drives the torsional wave instability. Very little covalent bonding is found between the chains and the nanotube sheath, leading to relatively unhindered longitudinal and torsional dynamics for the encapsulated chains.