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Novel switching transition in conducting polymer nanowires
Prof. Milan K. Sanyal（Surface Physics Division, Saha Institute of Nuclear Physics,1/AF Bidhannagar, Kolkata 700 064, India）
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We have observed [1,2] a novel switching transition to highly conducting state in conducting polymer (Polypyrrole) nanowires - the threshold voltage (current) of the observed transition can be easily tuned by changing diameter of nanowires [3] and/or temperature. Negative differential resistance, enhancement of noise above the threshold and several other similarities with sliding motion of charge density wave (CDW) observed in structurally ordered systems. We shall discuss all these results that give evidence in favor of Wigner crystallization [4] and nature of disorder in these nanowires. Electron crystallization due to Coulomb repulsion is expected [5] to be different here due to random localization.
References:
1. Rahman, A. and Sanyal, M.K., Adv. Mater. 19, 3956 (2007).
2. Rahman, A., Sanyal, M. K., Phys. Rev. B 76, 045110 (2007).
3. Rahman, A., Sanyal, M. K., Gangopadhayy, R., De, A., Chem. Phys. Lett. 447, 268 (2007).
4. Wigner E., Trans. Faraday Soc. 34, 678 (1938).
5. Slutskin, A. A., Pepper, M. and Kovtun, H. A., Europhys. Lett. 62, 705 (2003).
