Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 73: Heterostructures and Interfaces (Joint session of HL and O, organized by HL)

HL 73.3: Vortrag

Donnerstag, 10. März 2016, 10:00–10:15, H17

Epitaxial growth and conductivity mechanisms of [LaNiO₃/LaAlO₃]₁₀ superlattices — •Haoming Wei, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Exp. Physik II, Germany

LaNiO₃ (LNO) is an interesting material exhibiting Pauli paramagnetic metallic behavior in a wide temperature range. New properties can emerge in the LNO-based superlattices (SLs) by modifying the orbital, electronic, and magnetic structure of bulk LNO [1]. We have grown LNO, LaAlO₃ (LAO) films, and [LNO (d nm)/LAO (2 nm)]₁₀ SLs by plused laser deposition [2]. Sharp reflection high-energy electron diffraction patterns and atomic force microscopy images confirm an atomically flat surface. Reciprocal space maps reveal the in-plane lattice match of the SLs to the substrates. X-ray reflectivity data with strong Bragg reflections indicate abrupt interfaces of SLs with interfacial roughness in the order of one unit cell. A clear quantum confinement effect on the electronic properties including a metal-insulator transition (MIT) of the LNO/LAO SLs is demonstrated for decreasing LNO thickness. Single LNO films and SLs with LNO thickness of 4 nm show metallic behaviour at all temperatures. The SL with 2 nm thick LNO shows MIT due to the quantum interference of electronic waves. Strong localization appears when the LNO thickness of SLs reduced to 1.2 nm and two-dimensional variable range hopping is the main conduction mechanism.

[1] M. K. Stewart et al. J. Appl. Phys. 110, 033514 (2011).

[2] H. M. Wei et al. Appl. Phys. Lett. 106, 042103 (2015).