Selective growth of epitaxial Sr2IrO4 by controlling plume dimensions in pulsed laser deposition

We report thatepitaxial Sr2IrO4thin-films can be selectivelygrown usingpulsed laser deposition(PLD). Due to the competition between the Ruddlesden-Popper phases of strontium iridates (Srn+1IrnO3n+1), conventionalPLD methods often result in mixed phases of Sr2IrO4 (n  = 1), Sr3Ir2O7 (n  = 2), and SrIrO3 (n  = ∞). We have discovered that reducedPLD plume dimensions and slow deposition rates are the key for stabilizing pure Sr2IrO4 phasethin-films, identified by real-timein-situ monitoring of their optical spectra. The slow film deposition results in athermodynamically stable TiO2\\SrO\IrO2\SrO\SrO configuration at aninterface rather than TiO2\\SrO\SrO\IrO2\SrO between a TiO2-terminated SrTiO3 substrate and a Sr2IrO4thin film, which is consistent with other layered oxidesgrown bymolecular beam epitaxy. Our approach provides an effective method for usingPLD to achieve pure phasethin-films of layered materials that are susceptible to several energetically competing phases.

Source: Applied Physics Letters - November 14, 2016 Category: Physics Authors: S. S. A. Seo, J. Nichols, J. Hwang, J. Terzic, J. H. Gruenewald, M. Souri, J. Thompson, J. G. Connell and G. Cao Source Type: research