Mott gap collapse in lightly hole-doped Sr_2-xK_xIrO₄

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Strontium iridate (Sr2IrO4) exhibits properties analogous to cuprates, making its carrier doping behavior a key research area.
• Understanding the effects of hole doping on Sr2IrO4 is crucial for elucidating its intrinsic electronic properties.

Purpose of the Study:

• To investigate the electronic structure evolution of Sr2IrO4 upon hole doping.
• To synthesize and characterize hole-doped Sr2-xKxIrO4 and compare its properties to electron-doped counterparts.

Main Methods:

• Reactive oxide molecular-beam epitaxy for material synthesis.
• Substitutional diffusion for introducing potassium (hole dopant).
• In-situ angle-resolved photoemission spectroscopy (ARPES) for electronic structure determination.

Main Results:

• Successful synthesis of hole-doped Sr2-xKxIrO4.
• Observation of a coherent, two-band Fermi surface upon hole doping.
• Identification of both hole pockets at (π, 0) and electron pockets at (π/2, π/2).

Conclusions:

• Hole doping in Sr2IrO4 leads to a complex Fermi surface topology.
• The Fermi surface and band structure show remarkable similarities between hole- and electron-doped Sr2IrO4.
• These findings offer new insights into the electronic behavior of iridates and their relation to cuprates.