Magnetooptical Properties of Carbon Toroids

The π-electron states of carbon toroids are obtained from the tight-binding model. The low-frequency absorption spectra are studied within the gradient approximation. They exhibit rich peak structures, mainly owing to the inter-π-state and the intra-π-state excitations. In general, spectral intensity and excitation energies strongly depend on the toroidal geometry (chiral angle, radius, and width), the temperature (T), and the magnetic flux (ϕ). However, armchair carbon toroids only exhibit one special peak, and their absorption spectra are hardly affected by T and ϕ.