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.

29 pages, 8 figures

References in corpus (7)

• A `checkerboard' electronic crystal state in lightly hole-doped Ca_{2-x}Na_{x}CuO_{2}Cl_{2}
• An Intrinsic Bond-Centered Electronic Glass with Unidirectional Domains in Underdoped Cuprates
• Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature Superconductivity
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
• Spin-orbit tuned metal-insulator transitions in single-crystal Sr2Ir1-xRhxO4 (0\leqx\leq1)
• Atomic-scale fragmentation and collapse of antiferromagnetic order in a doped Mott insulator
• Flux growth of Sr(n+1)Ir(n)O(3n+1) [n=1, 2, infinity] crystals

Cited by in corpus (5)

• 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
• Evolution of the spectral lineshape at the magnetic transition in Sr2IrO4 and Sr3Ir2O7
• High-pressure floating zone crystal growth of Sr${}_2$IrO${}_4$