2016/08/17 by Zhen Xing, T. J. Huffman, Tyler J. Huffman +14
Business, Management and Accounting · Materials Science · Physics and Astronomy · #Charge carrier #Condensed matter physics #Corporate Taxation and Avoidance #Doping #Electrical resistivity and conductivity #Iron-based superconductors research #Materials science #Optics #Phase (matter) #Physics #Quantum mechanics #Rare-earth and actinide compounds #Scattering #Scattering rate #Tetragonal crystal system #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.94.064514
published as Physical Review B 94, 064514 (2016) · 13 pages
openalex publication_date 2016/08/17 · arxiv created 2016/08/31 · openalex created_date 2016/09/16 · arxiv updated 2016/09/21 · openalex updated_date 2026/08/05
We have investigated the charge dynamics and the nature of many-body interactions in La- and Pr- doped CaFe2As2. From the infrared part of the optical conductivity, we discover that the scattering rate of mobile carriers above 200 K exhibits saturation at the Mott-Ioffe-Regel limit of metallic transport. However, the dc resistivity continues to increase with temperature above 200 K due to the loss of Drude spectral weight. The loss of Drude spectral weight with increasing temperature is seen in a wide temperature range in the uncollapsed tetragonal phase, and this spectral weight is recovered at energy scales about one order of magnitude larger than the Fermi energy scale in these semimetals. The phenomena noted above have been observed previously in other correlated metals in which the dominant interactions are electronic in origin. Further evidence of significant electron-electron interactions is obtained from the presence of quadratic temperature and frequency-dependent terms in the scattering rate at low temperatures and frequencies in the uncollapsed tetragonal structures of La-doped and Pr-doped CaFe2As2. For temperatures below the structure collapse transition in Pr-doped CaFe2As2 at \ensuremath∼70\phantom\rule0.16em0exK, the scattering rate decreases due to weakening of electronic correlations, and the Drude spectral weight decreases due to modification of the low-energy electronic structure.