Bulk-Induced 1/f Noise at the Surface of Three-Dimensional Topological Insulators

Bhattacharyya, Semonti and Banerjee, Mitali and Nhalil, Hariharan and Islam, Saurav and Dasgupta, Chandan and Elizabeth, Suja and Ghosh, Arindam (2015) Bulk-Induced 1/f Noise at the Surface of Three-Dimensional Topological Insulators. In: ACS NANO, 9 (12). pp. 12529-12536.

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Abstract

Slow intrinsic fluctuations of resistance, also known as the flicker noise or 1/f-noise, in the surface transport of strong topological insulators (TIs) is a poorly understood phenomenon. Here, we have systematically explored the 1/f-noise in field-effect transistors (FET) of mechanically exfoliated Bi1.6Sb0.4Te2Se TI films when transport occurs predominantly via the surface states. We find that the slow kinetics of the charge disorder within the bulk of the TI induces mobility fluctuations at the surface, providing a new source of intrinsic 1/f-noise that is unique to bulk TI systems. At small channel thickness, the noise magnitude can be extremely small, corresponding to the phenomenological Hooge parameter gamma(H) as low as approximate to 10(-4), but it increases rapidly when channel thickness exceeds similar to 1 mu m. From the temperature (T)-dependence of noise, which displayed sharp peaks at characteristic values of T, we identified generation-recombination processes from interband transitions within the TI bulk as the dominant source of the mobility fluctuations in surface transport. Our experiment not only establishes an intrinsic microscopic origin of noise in TI surface channels, but also reveals a unique spectroscopic information on the impurity bands that can be useful in bulk TI systems in general.

Item Type:	Journal Article
Publication:	ACS NANO
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Keywords:	Topological Insulator; 1/f noise; generation-recombination noise
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	27 Jan 2016 06:48
Last Modified:	27 Jan 2016 06:48
URI:	http://eprints.iisc.ac.in/id/eprint/53181

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