Percolative Mott insulator-metal transition in doped Sr${}_2$IrO${}_4$

Abstract

Despite many efforts to rationalize the strongly correlated electronic ground states in doped Mott insulators, the nature of the doping induced insulator to metal transition is still a subject under intensive investigation. Here we probe the nanoscale electronic structure of the Mott insulator Sr${}_2$IrO${}_{4-\delta }$ with low-temperature scanning tunneling microscopy and find enhanced local density of states (LDOS) inside the Mott gap at the location of individual apical oxygen site defects. We visualize paths of enhanced conductance arising from the overlapping of defect states which induces finite LDOS at the Fermi level. By combining these findings with the typical spatial extension of isolated defects of about 2~nm, we show that the insulator to metal transition in Sr${}_2$IrO${}_{4-\delta }$ is of percolative nature.

arXiv comment29 pages, 8 figures

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Cited by in corpus (6)

• Evidence for a spinon Kondo effect in cobalt atoms on single-layer 1T-TaSe${}_2$
• Observation and manipulation of a phase separated state in a charge density wave material
• Single crystal growth of iridates without platinum impurities
• Local Density of States induced near Impurities in Mott Insulators
• Evolution of the spectral lineshape at the magnetic transition in Sr2IrO4 and Sr3Ir2O7
• High-pressure floating zone crystal growth of Sr${}_2$IrO${}_4$