Abstract:

Matter placed in a strong magnetic field provides a fascinating laboratory in which to study exotic quantum phenomena in a highly controllable manner. This talk will summarize our recent findings of novel magnetic properties of carbon nanotubes, graphene, and graphite, probed via high-­‐field magneto-­‐optical spectroscopy. A magnetic field applied parallel to a nanotube introduces an Aharonov-­‐Bohm phase to the electronic wave function, which leads to band gap oscillations, magnetic brightening of dark excitons, and extremely large magnetic susceptibility anisotropy. In graphene, a magnetic field applied perpendicular to the layer results in Landau quantization with non-­‐equal spacings; we highlight a novel situation where electron cyclotron resonance appears in the magnetic quantum limit even though the sample is p-­‐type. Finally, for graphite, we observe strongly temperature-­‐dependent, asymmetric spectral lines in electronic Raman spectra in magnetic fields up to 45 T applied along the c-­‐axis. The magnetic field quantizes the in-­‐plane motion while the out-­‐of-­‐plane motion remains free, effectively reducing the system dimension from three to one. Optically created electron-­‐hole pairs interact with, or “shake up,” the one-­‐ dimensional Fermi sea in the lowest Landau subbands, resulting in Fermi-­‐edge singularities.