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arXiv · 2001.05697

Optical Signature of a Crossover from Mott- to Slater-type Gap in Sr$_2$Ir$_{1-x}$Rh$_{x}$O$_{4}$

B. Xu·P. Marsik·E. Sheveleva·F. Lyzwa·A. Louat·V. Brouet·D. Munzar·C. Bernhard
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Abstract

With optical spectroscopy we provide evidence that the insulator-metal transition in Sr$_2$Ir$_{1-x}$Rh$_{x}$O$_{4}$ occurs close to a crossover from the Mott- to the Slater-type. The Mott-gap at $x = 0$ persists to high temperature and evolves without an anomaly across the N\'{e}el temperature, $T_N$. Upon Rh-doping, it collapses rather rapidly and vanishes around $x = 0.055$. Notably, just as the Mott-gap vanishes yet another gap appears that is of the Slater-type and develops right below $T_N$. This Slater-gap is only partial and is accompanied by a reduced scattering rate of the remaining free carriers, similar as in the parent compounds of the iron arsenide superconductors.

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B. Xu, P. Marsik, E. Sheveleva, F. Lyzwa, A. Louat, V. Brouet, D. Munzar, C. Bernhard. 2020-01-16. Optical Signature of a Crossover from Mott- to Slater-type Gap in Sr$_2$Ir$_{1-x}$Rh$_{x}$O$_{4}$. https://doi.org/10.1103/physrevlett.124.027402

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