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

Marsik, Premysl; Wang, Chen Nan; Rössle, Matthias; Yazdi-Rizi, M.; Schuster, Roman; Kim, Kyung Wan; Dubroka, Adam; Munzar, Dominik; Wolf, T.; Chen, X. H.; Bernhard, Christian

doi:10.1103/PhysRevB.88.180508

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

Marsik, Premysl University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Wang, Chen Nan University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Rössle, Matthias University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Yazdi-Rizi, M. University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Schuster, Roman University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Kim, Kyung Wan Department of Physics, Chungbuk National University, Cheongju, Korea
Dubroka, Adam Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic - CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
Munzar, Dominik Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic - CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
Wolf, T. Karlsruher Institut für Technologie, Institut für Festkörperphysik, Karlsruhe, Germany
Chen, X. H. Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
Bernhard, Christian University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland

15.11.2013

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Physical Review B. - 2014, vol. 88, no. 18, p. 180508

English 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.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

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