Photo-induced charge excitations in the copper oxide based antiferromagnetic Mott insulators are able to decay on extremely fast timescales owing to strong spin-charge coupling effects [1]. In recent years, the photo-carrier dynamics of the antiferromagnetic Mott insulator Sr₂IrO₄ has also become a subject of intensive study [2-4] owing to its similarity to the cuprates in terms of structural, electronic and magnetic properties. Here we examine how the photo-carrier relaxation dynamics of Sr₂IrO₄ vary with different excitation densities and excitation wavelengths, which access different inter-band transitions, using time-resolved optical reflectivity measurements. We will discuss our results in comparison to the cuprates.

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[2] Hsieh, D., et al., Phys. Rev. B 86, 035128 (2012)
[3] Dean, M.P.M., et al., Nature Materials (2016)
[4] Piovera, C., et al., Phys. Rev. B 93, 241114(R) (2016)