Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 105: Poster: Topological insulators (with MA/O)

HL 105.10: Poster

Donnerstag, 3. April 2014, 17:00–20:00, P1

Heteroepitaxial Li₂IrO₃ Thin Films Grown by Pulsed Laser Deposition — •Marcus Jenderka, Heiko Frenzel, Rüdiger Schmidt-Grund, Marius Grundmann, and Michael Lorenz — Institut für Experimentelle Physik II, Universität Leipzig, Linnéstraße 5, D-04103 Leipzig. Germany

The layered perovskite oxides A₂IrO₃ (A = Na, Li) have been studied in recent years in terms of a physical realization of spin-liquid [1] and topological insulator [2] phases, desired within certain quantum computation proposals. We report on the pulsed laser deposition of heteroepitaxial Li₂IrO₃ films on ZrO₂:Y(001) single crystalline substrates. As in Na₂IrO₃ [3], X-ray diffraction confirms a preferential (001) out-of-plane crystalline orientation with a defined in-plane epitaxial relationship. Resistivity between 35 and 300 K is dominated by a three-dimensional variable range hopping mechanism. Infrared optical transmission from 0 to 1.85 eV, measured by Fourier transform infrared spectroscopy (FTIR), reveals a small optical gap E_go ≈ 300 meV together with a splitting of the 5d-t_2g manifold caused by the interplay of spin-orbit coupling and electronic correlations. By means of infrared spectroscopic ellipsometry, the dielectric function (DF) is presented in the spectral range between 0.03 and 3.50 eV. The calculated absorption coefficient confirms the value for E_go.

[1] J. Chaloupka et al., Physical Review Letters 105, 027204 (2010).

[2] H.-S. Kim et al., Physical Review B 87, 165117 (2013).

[3] M. Jenderka et al., Physical Review B 88, 045111 (2013).