Electron transfer statistics and thermal fluctuations in molecular junctions

Goswami, Himangshu Prabal and Harbola, Upendra (2015) Electron transfer statistics and thermal fluctuations in molecular junctions. In: JOURNAL OF CHEMICAL PHYSICS, 142 (8).

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Abstract

We derive analytical expressions for probability distribution function (PDF) for electron transport in a simple model of quantum junction in presence of thermal fluctuations. Our approach is based on the large deviation theory combined with the generating function method. For large number of electrons transferred, the PDF is found to decay exponentially in the tails with different rates due to applied bias. This asymmetry in the PDF is related to the fluctuation theorem. Statistics of fluctuations are analyzed in terms of the Fano factor. Thermal fluctuations play a quantitative role in determining the statistics of electron transfer; they tend to suppress the average current while enhancing the fluctuations in particle transfer. This gives rise to both bunching and antibunching phenomena as determined by the Fano factor. The thermal fluctuations and shot noise compete with each other and determine the net (effective) statistics of particle transfer. Exact analytical expression is obtained for delay time distribution. The optimal values of the delay time between successive electron transfers can be lowered below the corresponding shot noise values by tuning the thermal effects. (C) 2015 AIP Publishing LLC.

Item Type:	Journal Article
Publication:	JOURNAL OF CHEMICAL PHYSICS
Publisher:	AMER INST PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Keywords:	QUANTUM TRANSPORT; SHOT-NOISE; PHOTONS; TRANSISTOR; EQUATIONS; SYSTEMS
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	21 Apr 2015 06:43
Last Modified:	21 Apr 2015 06:43
URI:	http://eprints.iisc.ac.in/id/eprint/51303

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