The study of structure, electronic and optical properties of double-walled carbon nanotube bundle under hydrostatic pressure

TL;DR

This study combines multiple computational methods to analyze how double-walled carbon nanotube bundles respond structurally, electronically, and optically to hydrostatic pressure, revealing stability mechanisms and phase transition signatures.

Contribution

It introduces a comprehensive multi-method approach to investigate pressure-induced effects on DWNT bundles, highlighting new stability insights and optical property changes.

Findings

Outer tube protects inner tube under pressure

Collapsed structures are more stable than herringbone

Optical properties show significant changes after collapse

Abstract

Combining a classical force field, a tight-binding model, and first-principles calculations, we have studied structural, electronic, and optical properties of double-walled carbon nanotube (DWNT) bundles under hydrostatic pressure. We find that the outer tube acts as a protection shield for the inner tube and the inner tube increases the structure stability and the ability to resist the pressure of the outer tube. Moreover, the collapsed structures of the double-walled carbon nanotube bundle called ``parallel'' and ``in-between'' are more stable than the one called ``herringbone''. The structural phase transition induces a pseudogap along symmetry line \textit{$\Gamma $X}. Furthermore, the optical properties change greatly after the collapse and a strong anisotropy appears in the collapsed structure. This provides an efficient experimental way to detect structural phase transitions in DWNT bundles.