  The spin-orbit coupling and electron correlation in perovskite SrIrO3 (SIO)
strongly favor new quantum states and make SIO very attractive for next
generation quantum information technology. In addition, the small electronic
band-width offers the possibility to manipulate anisotropic electronic
transport by strain. However, twinned film growth of SIO often masks electronic
anisotropy which could be very useful for device applications. We demonstrate
that the twinning of SIO films on (001) oriented SrTiO3 (STO) substrates can be
strongly reduced for thin films with thickness t less than 30 nm by using
substrates displaying a TiO2-terminated surface with step-edge alignment
parallel to the a- or b-axis direction of the substrate. This allows us to
study electronic anisotropy of strained SIO films which hitherto has been
reported only for bulk-like SIO. For films with t < 30 nm electronic anisotropy
increases with increasing t and becomes even twice as large compared to nearly
strain-free films grown on (110) DyScO3. The experiments demonstrate the high
sensitivity of electronic transport towards structural distortion and the
possibility to manipulate transport by substrate engineering.
