Structural properties and anisotropic electronic transport in SrIrO3 films

Perovskite SrIrO3 (SIO) films epitaxially deposited with a thickness of about 60 nm on various substrate materials display a nearly strain-relieved state. Films grown on orthorhombic (110) DyScO3 (DSO) are found to display an untwinned bulklike orthorhombic structure. However, film deposition on cubic (001) SrTiO3 (STO) induces a twinned growth of SIO. Resistance measurements on the SIO films reveal only weak temperature dependence, where the resistance R increases with decreasing temperature T. Hall measurements show dominant electronlike transport throughout the temperature range from 2 to 300 K. At 2 K, the electron concentration and resistivity for SIO on STO amounts to n(e) = 1.4 x 10(20) cm(-3) and 1 m Omega cm. Interestingly, the film resistance of untwinned SIO on DSO along the [1-10] and the [001] direction differs by up to 25%, indicating pronounced anisotropic electronic transport. The anisotropy of the resistance increases with decreasing T and displays a distinct maximum at around 86 K. The specific T dependence is similar to that of the structural anisotropy root(a(2) + b(2))/c of bulk SIO. Therefore, anisotropic electronic transport in SIO is very likely induced by the orthorhombic distortion. Consequently, for twinned SIO films on STO anisotropy vanishes nearly completely. The experimental results show that structural changes are very likely responsible for the observed anisotropic electronic transport. The strong sensitivity of the electronic transport in SIO films may be explained in terms of the narrow electronlike bands in SIO caused by spin-orbit coupling and orthorhombic distortion.