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Acoustic and optical phonon dynamics from femtosecond time-resolved optical spectroscopy of the superconducting iron pnictide Ca(Fe0.944Co0.056)(2)As-2

Kumar, Sunil and Harnagea, L and Wurmehl, S and Buchner, B and Sood, AK (2012) Acoustic and optical phonon dynamics from femtosecond time-resolved optical spectroscopy of the superconducting iron pnictide Ca(Fe0.944Co0.056)(2)As-2. In: EPL, 100 (5).

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Official URL: http://dx.doi.org/10.1209/0295-5075/100/57007

Abstract

We report the temperature evolution of coherently excited acoustic and optical phonon dynamics in the superconducting iron pnictide single crystal Ca(Fe0.944Co0.056)(2)As-2 across the spin density wave transition at T-SDW similar to 85 K and the superconducting transition at T-SC similar to 20 K. The strain pulse propagation model applied to the generation of the acoustic phonons yields the temperature dependence of the optical constants, and longitudinal and transverse sound velocities in the temperature range from 3.1 K to 300 K. The frequency and dephasing times of the phonons show anomalous temperature dependence below T-SC indicating a coupling of these low-energy excitations with the Cooper-pair quasiparticles. A maximum in the amplitude of the acoustic modes at T similar to 170 is seen, attributed to spin fluctuations and strong spin-lattice coupling before T-SDW. Copyright (c) EPLA, 2012

Item Type: Journal Article
Additional Information: Copyright for this article belongs to EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY, FRANCE
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Francis Jayakanth
Date Deposited: 22 Jan 2013 06:16
Last Modified: 22 Jan 2013 06:16
URI: http://eprints.iisc.ac.in/id/eprint/45673

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