1. Instituto de Física, Universidade de São Paulo, São Paulo, SP 05508-090, Brazil.
2. Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA.
3. Smalley-Curl Institute, Rice University, Houston, TX 77005, USA.
4. Department of Physics, The University of Texas at Austin, Austin, TX 78712, USA.
5. Department of Physics, Northeastern University, Boston, MA 02115, USA.
6. Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
7. Applied Physics Graduate Program, Smalley-Curl Institute, Rice University, Houston, TX 77005, USA.
8. Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan.
9. Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
10. Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP 12201-970, Brazil.
11. Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA.
12. Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA.