Doping dependence and electron-boson coupling in the ultrafast relaxation of hot electron populations in Ba(Fe1-xCox)(2)As-2

Avigo, I and Thirupathaiah, S and Ligges, M and Wolf, T and Fink, J and Bovensiepen, U (2016) Doping dependence and electron-boson coupling in the ultrafast relaxation of hot electron populations in Ba(Fe1-xCox)(2)As-2. In: NEW JOURNAL OF PHYSICS, 18 .

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Abstract

Using femtosecond time- and angle-resolved photoemission spectroscopy we investigate the effect of electron doping on the electron dynamics in Ba(Fe1-xCox)(2)As-2 in a range of 0 <= x < 0.15 at temperatures slightly above the Neel temperature. By analyzing the time- dependent photoemission intensity of the pump laser excited population as a function of energy, we found that the relaxation times at 0 < E - E-F < 0.2 eV are doping dependent and about 100 fs shorter at optimal doping than for overdoped and parent compounds. Analysis of the relaxation rates also reveals the presence of a pump fluence dependent step in the relaxation time at E - E-F = 200 meV which we explain by coupling of the excited electronic system to a boson of this energy. Wecompare our results with static ARPES and transport measurements and find disagreement and agreement concerning the doping-dependence, respectively. W ediscuss the effect of the electron-boson coupling on the energy-dependent relaxation and assign the origin of the boson to a magnetic excitation.

Item Type:	Journal Article
Publication:	NEW JOURNAL OF PHYSICS
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	03 Dec 2016 09:23
Last Modified:	03 Dec 2016 09:23
URI:	http://eprints.iisc.ac.in/id/eprint/55345

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