Nature of 1D Charge Transport Near Metal-Insulator Transitions in Carbon Nanotubes Dr. Swastik Kar DA 114 Wed 4 November 2009 4:00 PMPhysics Colloquium

The interplay of disorder and interactions, and its role in determining the nature of charge transport¹ especially in quantum-confined systems near a metal-insulator transition (MIT) remains one of the most fascinating areas of research in condensed matter physics. In this context, carbon nanotubes – a quasi 1D electronic system – demonstrates a variety of exotic physical phenomena and provides an ideal platform for investigations of various aspects of 1D physics. Exciting new results of 1D mesoscopic physics can be obtained by controlling locally inhomogeneous electrostatic and magnetic fields, e-e interaction strength and disorder density, and the electronic band structures of carbon nanotubes. In this talk, a number of innovative ways will be described that drives carbon nanotubes through different kinds of MITs. The behavior of various transport properties, as individual single- and multi-wall carbon nanotubes are driven through the MIT, will be presented. Topics will include metal-insulator transitions in single-wall carbon nanotubes², Lüttinger-liquid to Al'tshuler-Aronov transition and suppression of phase coherence by e-e interactions in disordered, many-channel carbon nanotubes³, effect of local nanoscale magnetism and superparamagnetism on transport in carbon nanotubes⁴, and the effect of metal nanocluster decoration on the electronic structure and transport properties of single-wall carbon nanotubes⁵. These results will be discussed within the framework of relevant models and phenomenological descriptions of electronic transport in 1D systems.

References:
1. Observation of non-Gaussian conductance fluctuations at low temperatures in Si:P(B) at the metal-insulator transition, S. Kar, A. K. Raychaudhuri, A. Ghosh, H. v. Lohneysen and G. Weiss, Physical Review Letters 91, 216603 (2003)
2. Metal-Semiconductor Transition in Single-Walled Carbon Nanotubes Induced by Low-Energy electron Irradiation, A. Vijayaraghavan, K. Kanzaki, S. Suzuki,Y. Kobayashi, H. Inokawa, Y. Ono, S. Kar, P.M Ajayan, Nano Letters 5, 1575 (2005)
3. Lüttinger Liquid to Al’tshuler-Aronov Transition in Disordered, Many-Channel Carbon Nanotubes, S. Kar*, C. Soldano*, L. Chen, S. Talapatra, R. Vajtai, S.K. Nayak and P.M. Ajayan, ACS Nano 3, 207 (2009)
4. Detection of Nanoscale Ferromagnetic Activity using a Single Carbon Nanotube, C. Soldano*, S. Kar*, S. Talapatra, S.K. Nayak and P.M. Ajayan, Nano Letters 8, 4498 (2008)
5. Highly Aligned Scalable Platinum-decorated Single-wall Carbon Nanotube Arrays for Nanoscale Electrical Interconnects, Young Lae Kim, Bo Li, Xiaohong An, Myung Gwan Hahm, Li Chen, Morris Washington, P.M. Ajayan, Saroj K. Nayak, Ahmed Busnaina, Swastik Kar*, and Yung Joon Jung*, ACS Nano 3 2818 (2009)