Signatures of superconducting and pseudogap phases in ultrafast transient reflectivity of Ca(Fe0.927Co0.073)(2)As-2

Kumar, Sunil and Harnagea, L and Wurmehl, S and Buechner, B and Sood, AK (2014) Signatures of superconducting and pseudogap phases in ultrafast transient reflectivity of Ca(Fe0.927Co0.073)(2)As-2. In: EPL, 105 (4).

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Abstract

We present femtosecond time-resolved pump-probe spectroscopic studies of a pseudogap (PG) along with the superconducting (SC) gap in an overdoped iron pnictide Ca(Fe0.927Co0.073)(2)As-2. It is seen that the temperature evolution of the photo-excited quasiparticle (QP) relaxation dynamics, coherently excited A(1g)-symmetric optical phonon and two acoustic phonon dynamics behave anomalously in the vicinity of the superconducting transition temperature T-c. A continuous change in the sign of the experimentally measured transient differential reflectivity Delta R/R signal at the zero time delay between the pump and probe pulses at a temperature of similar to 200K is inferred as an evidence of the emergence of the PG phase around that temperature. This behavior is independent of the pump photon energy and occurs for crystals without the spin density wave phase transition. Copyright (C) EPLA, 2014

Item Type:	Journal Article
Publication:	EPL
Publisher:	EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY
Additional Information:	Copyright for this article belongs to the EPL ASSOCIATION, FRANCE
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 May 2014 08:04
Last Modified:	22 May 2014 08:04
URI:	http://eprints.iisc.ac.in/id/eprint/48991

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