H. Ajiki | Searcharxiv

arXiv2010

Large Magnetic Susceptibility Anisotropy of Metallic Carbon Nanotubes

Through magnetic linear dichroism spectroscopy, the magnetic susceptibility anisotropy of metallic single-walled carbon nanotubes has been extracted and found to be 2-4 times greater than values for semiconducting single-walled carbon nanotubes. This large anisotropy is consistent with our calculations and can be understood in terms of large orbital paramagnetism of electrons in metallic nanotubes arising from the Aharonov-Bohm-phase-induced gap opening in a parallel field. We also compare our values with previous work for semiconducting nanotubes, which confirm a break from the prediction that the magnetic susceptibility anisotropy increases linearly with the diameter.

cond-mat.mes-hall↗

arXiv2003

Novel approach to nonlinear susceptibility

The calculation of the third order susceptibility still is a long standing fundamental problem of particular importance in nonlinear nanooptics: Indeed, cancellation of size-dependent terms coming from uncorrelated excitations is expected, but up to now shown for very simple Hamiltonians only. Using a many-body theory recently developed to handle interacting close-to-bosons, we prove it here for \emph{arbitrary} H. This new formalism actually provides the first clean way to calculate nonlinear susceptibilities, with results different from previous ones.

cond-mat.mes-hall↗