Signatures of Chemical Dopants in Simulated Resonance Raman Spectroscopy of Carbon Nanotubes

Single-walled carbon nanotubes (SWCNTs) with organic sp2- or sp3-hybdridization defects allow for robust tunability in many optoelectronic properties in these topologically interesting quasi-one-dimensional materials. Recent resonant Raman experiments have discovered new features in the intermediate frequency region upon functionalization and change with the degree of functionalization as well as with interactions between defect sites. In this letter, we report ab initio simulated near-resonant Raman spectroscopy results for pristine and chemically functionalized SWCNT models and find new features concomitant to experimental observations. We are able to assign the character of these features by varying the frequency of the external Raman laser frequency near the defect-induced E11* optical transition using a perturbative treatment to the electronic structure of the system. Obtained insights establish relationships between nanotube atomistic structure and Raman spectra facilitating further exploration of SWCNTs with tunable optical properties tuned by chemical doping.