Significant role of local atomic displacements on the non-monotonic electronic transport in Sm-doped Sr2−xSmxIrO4 system

Abstract

For the Sr2IrO4-based system, recent work pointed out the non-monotonic electronic transport property in Sm-doped Sr2−xSmxIrO4 compounds. In this contribution, x-ray absorption spectroscopy was applied to investigate the microscopic mechanism of the non-monotonic effect in terms of local atomic structure. Sm dopants can finely modulate the local atomic displacements of Sr2−xSmxIrO4, i.e. the in-plane IrO1Ir bond angle and the regularity of IrO6 octahedra. Upon Sm doping, the IrO1Ir bond angle θ increases monotonically. Interestingly, the IrO6 octahedra firstly become more regular with Sm doping, and then become more distorted, which is in line with the non-monotonic trend of electronic transport in Sr2−xSmxIrO4. The present results suggest that the regularity of IrO6 octahedra rather than the in-plane IrO1Ir bond angle that dominates the non-monotonic electronic transport of Sr2−xSmxIrO4 system.