The atoms are contained inside a carbon nanotube (CNT) and this is said to create a true one-dimensional material. The team says it has also shown that it is possible to alter the shape and electronic behaviour of the nanowires by varying the diameters of the tubes which encapsulate them.
The Cambridge researchers first used computer simulations to predict the types of geometric structures that would form if tellurium atoms were injected into nanotubes, and found that 1D wires could exist in such a scenario. Later, lab tests, using advanced techniques for synthesis and atomic-resolution visualisation, were performed by the Warwick researchers to confirm the theoretical predictions.
Tellurium normally behaves as a semiconductor, but when injected into carbon nanotubes and confined to one dimension, it starts behaving like a metal. Additionally, while the confinement provided by the CNTs can induce drastic changes in the way that tellurium behaves, the nanotubes themselves do not interact in any other way with the tellurium nanowires.
“When working with materials at very small scales such as this, the material of interest typically needs to be deposited onto a surface, but the problem is that these surfaces are normally very reactive,” said Paulo Medeiros of Cambridge’s Cavendish Laboratory. “But carbon nanotubes are chemically quite inert, so they help solve one of the problems when trying to create truly 1D materials.
“However, we’re just starting to understand the physics and chemistry of these systems – there’s still a lot of basic physics to be uncovered.”