Raman Spectroscopy of Individual Carbon Nanotubes Under Strain
S.B. Cronin, M. Tinkham, and E. Demler

Raman spectroscopy of individual semiconducting carbon nanotubes is used for the first time to measure vibrational frequencies vs. strain. The strain is induced by bending the nanotubes with an AFM tip while the ends of the nanotubes are held fixed by metal electrodes, thus converting the transverse displacement to an elongation. Under strain of 1–2%, we observe the vibrational frequency to decrease by up to 40cm^–1. The Raman peaks shift back toward their original positions over a time period of order one week, implying strain relaxation over a similar period.