Prof Arzhang Ardavan

Abstract:

The interlayer magnetoresistance ρzz of the organic metal κ-(BEDTTTF)2Cu(NCS)2 has been studied in fields B of up to 45 T and at temperatures T from 0.5 K to 50 K. The peak in ρzz seen in exactly in-plane fields, a definitive signature of interlayer coherence, remains to Ts exceeding the Anderson criterion for incoherent transport by a factor ∼ 25. Angle-dependent magnetoresistance oscillations (AMROs) due to Fermi-surface orbits are suppressed by rising T, with a T2dependence suggesting electron-electron scattering. © 2006 IOP Publishing Ltd.

Abstract:

Er3N@C80 exhibits sharp optical emission lines in the near-infrared attributed to fluorescence from the Er³⁺ ion. Here we demonstrate that high magnetic fields cause this spectrum to split, corresponding to transitions from the lowest field-split Kramers doublet of the ⁴I13/2 manifold to the four lowest field-split levels of the ⁴I15/2 manifold. The internal structure of these fullerenes can be spatially aligned with a preferred orientation under high magnetic field; the effect of alignment is to reduce the broadening associated with the isotropic spatial averaging characteristic of powder or frozen-solution spectra. Using a tunable 1.5 μm laser, we directly observe non-cage-mediated optical interactions with the Er³ ion. This spectroscopic method provides the opportunity to map the energy level structure of the incarcerated ion and to coherently control its quantum state. These qualities suggest that rare-earth endohedral fullerenes have characteristics that could be employed as a readout pathway for fullerene-based quantum information processing. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.