"Infrared study of the electronic structure of the metallic pyrochlore iridate Bi2Ir2O7"

Y. S. Lee,: S. J. Moon, Scott C. Riggs, M. C. Shapiro, I. R. Fisher, Bradford W. Fulfer, Julia Y. Chan, A. F. Kemper, and D. N. Basov; Physical Review B, 05/30/13.

Additional Authors: S. J. Moon, Scott C. Riggs, M. C. Shapiro, I. R. Fisher, Bradford W. Fulfer, Julia Y. Chan, A. F. Kemper, and D. N. Basov

Abstract:

We investigated the electronic properties of a single crystal of metallic pyrochlore iridate Bi2Ir2O7 by means of infrared spectroscopy. Our optical conductivity data show the splitting of t2g bands into Jeff ones due to strong spin-orbit coupling. We observed a sizable midinfrared absorption near 0.2 eV which can be attributed to the optical transition within the Jeff,1/2 bands. More interestingly, we found an abrupt suppression of optical conductivity in the very far-infrared region. Our results suggest that the electronic structure of Bi2Ir2O7 is governed by the strong spin-orbit coupling and correlation effects, which are a prerequisite for theoretically proposed nontrivial topological phases in pyrochlore iridates.