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arXiv · 1303.5245

Mott Variable Range Hopping and Weak Antilocalization Effect in Heteroepitaxial Na2IrO3 Thin Films

Marcus Jenderka·José Barzola-Quiquia·Zhipeng Zhang·Heiko Frenzel·Marius Grundmann·Michael Lorenz
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Abstract

Iridate thin films are a prerequisite for any application utilizing their cooperative effects resulting from the interplay of stron spin-orbit coupling and electronic correlations. Here, heteroepitaxial Na2IrO3 thin films with excellent (001) out-of-plane crystalline orientation and well defined in-plane epitaxial relationship are presented on various oxide substrates. Resistivity is dominated by a three-dimensional variable range hopping mechanism in a large temperature range between 300 K and 40 K. Optical experiments show the onset of a small optical gap of about 200 meV and a splitting of the Ir 5d-t2g manifold. Positive magnetoresistance below 3 T and 25 K shows signatures of a weak antilocalization effect. This effect can be associated with surface states in a topological insulator and hence supports proposals for a topological insulator phase present in Na2IrO3.

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Marcus Jenderka, José Barzola-Quiquia, Zhipeng Zhang, Heiko Frenzel, Marius Grundmann, Michael Lorenz. 2013-03-21. Mott Variable Range Hopping and Weak Antilocalization Effect in Heteroepitaxial Na2IrO3 Thin Films. https://doi.org/10.1103/physrevb.88.045111

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