Optical investigations on $Y_{2-x}B{i}_{x}R{u}_2{O}_7$: Electronic structure evolutions related to the metal-insulator transition

Abstract

Optical conductivity spectra of cubic pyrochlore $Y_{2-x}B{i}_{x}R{u}_2{O}_7$ (0.0$\le${\it x}$\le$2.0) compounds are investigated. As a metal-insulator transition (MIT) occurs around {\it x}$=$0.8, large spectral changes are observed. With increase of {\it x}, the correlation-induced peak between the lower and the upper Hubbard bands seems to be suppressed, and a strong mid-infrared feature is observed. In addition, the $p-d$ charge transfer peak shifts to the lower energies. The spectral changes cannot be explained by electronic structural evolutions in the simple bandwidth-controlled MIT picture, but are consistent with those in the filling-controlled MIT picture. In addition, they are also similar to the spectral changes of Y${}_{2-x}$Ca${}_x$Ru${}_2$O${}_7$ compounds, which is a typical filling-controlled system. This work suggests that, near the MIT, the Ru bands could be doped with the easily polarizable Bi cations.

arXiv comment5 figures

References in corpus (9)

• Integer filling metal insulator transitions in the degenerate Hubbard model
• Core-Level X-Ray Photoemission Satellites in Ruthenates: A New Mechanism Revealing the Mott Transition
• Optical investigation on the electronic structures of Y_{2}Ru_{2}O_{7}, CaRuO_{3}, SrRuO_{3}, and Bi_{2}Ru_{2}O_{7}
• LiV${}_2$O${}_4$: frustration induced heavy fermion metal
• Mott transition and heavy fermion state in the pyrochlore Hubbard model
• Geometrical frustration induced (semi-)metal to insulator transition
• Spectral functions in itinerant electron systems with geometrical frustration
• Optical evidence for mass enhancement of quasiparticles in pyrochlore Cd${}_2$Re${}_2$O${}_7$
• Optical properties of pyrochlore oxide $P{b}_{2}R{u}_2{O}_{7-\delta }$

Cited by in corpus (3)

• Self-Doping Induced Orbital-Selective Mott Transition in Hg2Ru2O7
• Evolution of the electronic structure across the filling-control and bandwidth-control metal-insulator transitions in pyrochlore-type Ru oxides
• Optical conductivity of the metallic pyrochlore iridate Pr${}_2$Ir${}_2$O${}_7$: Influence of spin-orbit coupling and electronic correlations on the electronic structure