Shot noise reveals correlated hopping electron transport in SrIrO3

SrIrO₃ is a metallic complex oxide with unusual electronic and magnetic properties believed to originate from electron correlations due to its proximity to Mott metal-insulator transition, which remain poorly understood. We studied shot noise produced by SrIrO₃ nanojunctions. The junctions exhibit strong shot noise suppression and enhanced thermal broadening of noise dependence on bias, demonstrating that conduction is through charge hopping instead of diffusion. However, SrIrO₃ does not show low-temperature resistivity divergence expected for single-particle hopping. Additionally, shot noise exhibits anomalous scaling with junction length, suggesting a dominant role of electron correlations. We propose that these properties can be explained by charge hopping along quasi-1D conduction paths confined by Mott singlet correlations. These findings provide insight into the non-Fermi liquid state of SrIrO₃, which may be relevant to other materials close to Mott transition such as high-temperature superconductors.