Prof Arzhang Ardavan

Abstract:

The endohedral fullerene Er3N@C80 shows characteristic 1.5 μm photoluminescence at cryogenic temperatures associated with radiative relaxation from the crystal-field split Er3+ 4I13/2 manifold to the 4I15/2 manifold. Previous observations of this luminescence were carried out by photoexcitation of the fullerene cage states leading to relaxation via the ionic states. We present direct non-cage-mediated optical interaction with the erbium ion. We have used this interaction to complete a photoluminescence-excitation map of the Er3+ 4I13/2 manifold. This ability to interact directly with the states of an incarcerated ion suggests the possibility of coherently manipulating fullerene qubit states with light. © 2006 Elsevier B.V. All rights reserved.

Abstract:

We have measured the thermopower and Nernst effects in the quasi-one-dimensional organic molecular metal (TMTSF)2 Cl O4 as a function of temperature and magnetic field strength and orientation. At 10 K this material exhibits a maximum Nernst coefficient of 12 μVKT, one of the largest ever observed in a metal. The thermoelectric effects are very sensitive to the reconstruction of the band structure caused by the Cl O4 anion ordering. © 2006 The American Physical Society.

Abstract:

We have produced the fullerene dimers C(120), C(120)O, and C(120)O(2) by a high-speed vibration milling technique. The thermal stability of C(120), C(120)O, and C(120)O(2) has been studied in the temperature range 150-350 degrees C for up to 4 h under vacuum. The bridging oxygen atoms were found to substantially increase the stability of the fullerene dimer molecules.