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Ultrafast quasiparticle relaxation dynamics in superconducting iron pnictide Ca(Fe0.944Co0.056)(2)As-2

Kumar, Sunil and Harnagea, L and Wurmehl, S and Buchner, B and Sood, AK (2013) Ultrafast quasiparticle relaxation dynamics in superconducting iron pnictide Ca(Fe0.944Co0.056)(2)As-2. In: Solid State Communications, 160 . pp. 8-12.

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Official URL: http://dx.doi.org/10.1016/j.ssc.2013.02.008


Nonequilibrium quasiparticle relaxation dynamics is reported in superconducting Ca(Fe0.944Co0.056)(2)As-2 single crystals by measuring transient reflectivity changes using femtosecond time-resolved pump-probe spectroscopy. Large changes in the temperature-dependent differential reflectivity values in the vicinity of the spin density wave (T-SDW) and superconducting (T-SC) transition temperatures of the sample have been inferred to have charge gap opening at those temperatures. We have estimated the zero-temperature charge gap value in the superconducting state to be similar to 1.8k(B)T(SC) and an electron-phonon coupling constant lambda of similar to 0.1 in the normal state that signifies the weak coupling in iron pnictides. From the peculiar temperature-dependence of the quasiparticle dynamics in the intermediate temperature region between T-SC and T-SDW we infer a temperature scale where the charge gap associated with the spin ordered phase is maximum and closes on either side while approaching the two phase transition temperatures.

Item Type: Journal Article
Publication: Solid State Communications
Publisher: Elsevier Science
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Iron pnictide; Superconductivity; Ultrafast Spectroscopy
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 18 Jun 2013 11:46
Last Modified: 18 Jun 2013 11:46
URI: http://eprints.iisc.ac.in/id/eprint/46730

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