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arXiv · 1411.2041

High-energy electronic excitations in Sr$_2$IrO$_4$ observed by Raman scattering

Jhih-An Yang·Yi-Ping Huang·Michael Hermele·Tongfei Qi·Gang Cao·Dmitry Reznik
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Abstract

Spin-orbit interaction in Sr$_2$IrO$_4$ leads to the realization of the $J_{\mathrm{eff}}$ = 1/2 state and also induces an insulating behavior. Using large-shift Raman spectroscopy, we found two high-energy excitations of the d-shell multipletat at 690 meV and 680 meV with $A_{1g}$ and $B_{1g}$ symmetry respectively. As temperature decreases, the $A_{1g}$ and $B_{1g}$ peaks narrow, and the $A_{1g}$ peak shifts to higher energy while the energy of the $B_{1g}$ peak remains the same. When 25$\%$ of Ir is substituted with Rh the $A_{1g}$ peak softens by 10$\%$ but the $B_{1g}$ peak does not. We show that both pseudospin-flip and non-pseudosin-flip dd electronic transitions are Raman active, but only the latter are observed.

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Jhih-An Yang, Yi-Ping Huang, Michael Hermele, Tongfei Qi, Gang Cao, Dmitry Reznik. 2015-07-13. High-energy electronic excitations in Sr$_2$IrO$_4$ observed by Raman scattering. https://doi.org/10.1103/physrevb.91.195140

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