High Pressure Study on Carbon Nanotubes – Interesting Even Before Phase Transition

Series: 
CCMMP Seminars
Speaker: 
Mr Yiwei Sun
Host: 
Prof David Dunstan
Date: 
October 14th, 2014 at 14:00
Room: 
GO Jones Room 610
Abstract: 

High pressure research has drawn much attention due to the development of both theoretical and experimental techniques, in predicting and confirming new structure under higher and higher pressure. The behaviour of materials under pressure before the phase transition is well described by laws of classical mechanics and mostly understood by semi-classical atomic models. Carbon nanotubes, as one of the stiffest materials yet discovered, remain structurally stable in GPa range. The problem merges – different research groups report different Carbon nanotubes behaviour under pressure (the pressure dependence of the stiff sp2 bond). In this talk, I will show how we experimentally try to identify the diameter, chirality, laser excitation, solvent and bundling effects on this pressure dependence, and theoretically try to understand them by studying the π-electrons behaviour. All these effects are negligible before GPa range and appear in this study.