Mott gap collapse in lightly hole-doped Sr<sub>2-x</sub>K<sub>x</sub>IrO<sub>4</sub>.

Nelson, J N; Parzyck, C T; Faeth, B D; Kawasaki, J K; Schlom, D G; Shen, K M · Nat Commun · 2020

basic_science · Level V

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Abstract

The evolution of Sr2IrO4 upon carrier doping has been a subject of intense interest, due to its similarities to the parent cuprates, yet the intrinsic behaviour of Sr2IrO4 upon hole doping remains enigmatic. Here, we synthesize and investigate hole-doped Sr2-xKxIrO4 utilizing a combination of reactive oxide molecular-beam epitaxy, substitutional diffusion and in-situ angle-resolved photoemission spectroscopy. Upon hole doping, we observe the formation of a coherent, two-band Fermi surface, consisting of both hole pockets centred at (π, 0) and electron pockets centred at (π/2, π/2). In particular, the strong similarities between the Fermi surface topology and quasiparticle band structure of hole- and electron-doped Sr2IrO4 are striking given the different internal structure of doped electrons versus holes.