Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 106: Complex Oxides: Bulk Properties, Surfaces and Interfaces (joint session TT/MA/KFM)

TT 106.8: Vortrag

Freitag, 16. März 2018, 11:30–11:45, H 0110

Intrinsic defects effects to the electronic structure of Sr₂IrO₄ probed by scanning tunneling microscopy — •Zhixiang Sun¹, Jose M. Guevara¹, Ekaterina M. Pärschke¹, Steffen Sykora¹, Kaustuv Manna^1,2, Johannes Schoop¹, Andrey Malyuk¹, Sabine Wurmehl^1,3, Jeroen van den Brink¹, Bernd Büchner^1,3, and Christian Hess¹ — ¹IFW-Dresden, 01069 Dresden — ²MPI-CPfS, 01187 Dresden — ³Institute for Solid State Physics, TU Dresden

Due to its similarity to cuprates, there is tremendous interest on the possible superconducting ground-state in doped Sr₂IrO₄ (Ir214). Nevertheless, it has been found that doping of Ir214 is difficult. The mechanism of dopant induced insulator to metal transition (IMT) has not been fully clarified. We have carried out low temperature scanning tunneling microscopy/spectroscopy experiments on Ir214 crystals. Several different types of intrinsic defects have been identified and their effects to the local electronic structure have been probed. We noticed that for the apical oxygen site defects, their effects are spatially very localized (< 2 nm). Also on the spectra taken on top of these defects, in gap states with a charge transfer like behavior are observed. With a local defect model we simulated the spectra, which gives good a match with the results. Our results provide important observations on the effects of individual defects on the local electronic properties. This is crucial for further tailoring the electronic structure of Ir214. Furthermore, they can also facilitate the understanding of the general mechanism of IMT in Mott insulators.