Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1−xLax)3Ir2O7

Abstract

We report on infrared spectroscopic studies of the electronic response of the (Sr1−xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1−xLax)3Ir2O7 system.

Infrared probe of pseudogap in electron-doped Sr2IrO4

“…Figures 4(a) and (b) illustrate that (Sr 1− x La x ) 2 IrO 4 has a stronger propensity for localizing the doped charge carriers. Although less electrons are doped in (Sr 0.949 La 0.051 ) 3 Ir 2 O 7 (7.65% electrons/Ir doping) than in (Sr 0.933 La 0.067 ) 2 IrO 4 (13.4% electrons/Ir doping), a coherent Drude-like peak without any trace of the pseudogap is registered in the bilayer compound 39 . The evolutions of the SW’s of the peaks α and β also support the notion of the stronger tendency for charge localization in the single-layer system.…”

Doping-dependent correlation effects in (Sr1−xLax)3Ir2O7Affeldt1, Hogan2, Denlinger3 et al. 2018Phys. Rev. B3022View full textAdd to dashboardCite

“…Much recent progress has been made in understanding the nature of the spin-orbit Mott state in the layered perovskite iridates 2,3,6,[12][13][14][16][17][18]24,[27][28][29]32,36 , in which spin-orbit coupling and Coulomb electron-electron correlations combine to form an insulating state. The spinorbit coupling arranges the t 2g bands by an effective angular momentum into a filled J eff = 3 2 state and a half-filled J eff = 1 2 state.…”

Doping-driven structural distortion in the bilayer iridate (Sr1−xLax)3Ir2O

“…11 The metallic state realized beyond this transition is unconventional with signatures of strong correlation effects, 16 dimer formation, 17,18 negative electronic compressibility, 14 and other electronic anomalies. 19,20 One of the anomalous properties inherent to (Sr 1−x La x ) 3 Ir 2 O 7 is the appearance of a structural distortion below a characteristic temperature T S .…”