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arXiv · 1309.3198

Low-energy interband transitions in the infrared response of Ba(Fe1-xCox)2As2

P. Marsik·C. N. Wang·M. Roessle·M. Yazdi-Rizi·R. Schuster·K. W. Kim·A. Dubroka·D. Munzar·T. Wolf·X. H. Chen·C. Bernhard
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Abstract

We studied the doping and temperature (T) dependence of the infrared (IR) response of Ba(Fe1-xCox)2As2 single crystals. We show that a weak band around 1000 cm-1, that was previously interpreted in terms of interaction of the charge carriers with magnetic excitations or of a pseudogap, is rather related to low-energy interband transitions. Specifically, we show that this band exhibits a similar doping and T-dependence as the hole pockets seen by angle resolved photoemission spectroscopy (ARPES). Notably, we find that it vanishes as a function of doping near the critical point where superconductivity is suppressed in the overdoped regime. Our IR data thus provide bulk specific information (complementary to the surface sensitive ARPES) for a Lifshitz transition. Our IR data also reveal a second low-energy band around 2300 cm-1 which further emphasizes the necessity to consider the multiband nature of these iron arsenides in the analysis of the optical response.

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P. Marsik, C. N. Wang, M. Roessle, M. Yazdi-Rizi, R. Schuster, K. W. Kim, A. Dubroka, D. Munzar, T. Wolf, X. H. Chen, C. Bernhard. 2013-09-12. Low-energy interband transitions in the infrared response of Ba(Fe1-xCox)2As2. https://doi.org/10.1103/physrevb.88.180508

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