Condensed-Matter Physics & Materials Science Seminar
"Incoherent Charge Dynamics and Role of Electronic Correlations in Iron Pnictides"
Presented by Shin-ichi Uchida, University of Tokyo, Japan
Thursday, November 7, 2013, 1:30 pm
Small Seminar Room, Bldg. 510
Hosted by: John P. Hill
We have carried out a comparative study of the in-plane resistivity and the optical conductivity spectrum of BaFe2As2 and other transition-metal pnictides with the same crystal structure, including BaCo2As2, BaFe2P2, and KFe2As2, which are linked with BaFe2As2 via chemical substitution (doping). It is found that, in the high-temperature phase, charge dynamics is highly incoherent with coherent Drude component occupying an only small fraction of the low-energy spectral weight for the two iron arsenides, BaFe2As2 and KFe2As2 , whereas it is highly coherent for the other pnictides. The fraction of the coherent Drude spectral weight in the low-energy spectrum, the degree of coherence, is found to be well correlated with the transition metal (TM)-pnictogen bond angle and the electron filling of TM-3d orbitals indicating that electronic correlations are strong in iron arsenides and that doping controls the correlation strength in different ways depending on the type of doping and the dopant site.  M. Nakajima, S. Ishida, H. Eisaki, S. Uchida et al., "Normal-state char ge dynamics in doped BaFe2As2: Roles of doping and necessary ingredients for superconductivity", arXiv: 1308.6133.  M. Nakajima, S. Ishida, H. Eisaki, S. Uchida et al., " Strong electronic correlations in iron pnictides: Comparison of the3 optical spectra for BaFe2As2-related compounds", arXiv: 1308.6113.