Raman spectroscopy of strained single-walled carbon nanotubes.

Due to remarkable rolling structure and distinct rolling direction, the chirality-dependent Raman spectra of single-walled carbon nanotubes (SWNTs) show two characteristic features: the radial breathing mode (RBM) and the G-band. Rich information about SWNTs presented by these Raman features makes Raman spectroscopy a general and common tool for characterizing structures and properties of SWNTs and their changes. When exerted by external forces, the geometrical structures of SWNTs will change, which further affects the electronic structures and phonon properties of SWNTs. In this article, emphasis is given to how Raman frequency and resonant-Raman intensity evolve under distinct strains, including uniaxial strain, torsional strain, radial deformation and bending deformation. It is found that depending on different structural variations, Raman spectra of SWNTs have different responses to each strain, showing that resonant-Raman spectroscopy is a suitable tool to characterize and study strains in SWNTs.