Orthorhombic vs. hexagonal epitaxial SrIrO₃ thin films: Structural stability and related electrical transport properties

¹ Department of Physics, Indian Institute of Science - Bangalore 560012, India
² EMAT, University of Antwerp - Groenenborgerlaan 171, 2020 Antwerp, Belgium
³ Centre for Nano Science and Engineering (CeNSE), Indian Institute of Science - Bangalore 560012, India
⁴ Institute of Physics, Sachivalaya Marg - Bhubaneswar 751005, India
⁵ Homi Bhabha National Institute - Anushakti Nagar, Mumbai 400085, India

^(a) shwetha@iisc.ac.in

Received: 25 February 2018
Accepted: 28 May 2018

Abstract

Metastable orthorhombic SrIrO₃ (SIO) is an arch-type spin-orbit coupled material. We demonstrate here a controlled growth of relatively thick (200 nm) SIO films that transform from bulk “6H-type” structure with monoclinic distortion to an orthorhombic lattice by controlling growth temperature. Extensive studies based on high-resolution X-ray diffraction and transmission electron microscopy infer a two distinct structural phases of SIO. Electrical transport reveals a weak temperature-dependent semi-metallic character for both phases. However, the temperature-dependent Hall-coefficient for the orthorhombic SIO exhibits a prominent sign change, suggesting a multiband character in the vicinity of E_F. Our findings thus unravel the subtle structure-property relation in SIO epitaxial thin films.