  Orthorhombic SrIrO3 is a typical spin-orbit-coupling correlated metal that
shows diversified physical properties under the external stimuli. Here
nonlinear Hall effect and weakly temperature-dependent resistance are observed
in a SrIrO3 film epitaxially grown on SrTiO3 substrate. It infers that
orthorhombic SrIrO3 is a semimetal oxide. However, linear Hall effect and
insensitive-temperature-dependent resistance are observed in SrIrO3 films grown
on (La,Sr)(Al,Ta)O3 (LSAT) substrates, suggesting a tunable semimetallic state
due to band structure change in SrIrO3 films under different compressive
strain. The mechanism of this evolution is explored in detail through
strain-state analysis by reciprocal space mapping and electron diffraction,
carrier density and mobility calculations, as well as electronic band structure
evolution under compressive strain (predicted by tight-binding approximation).
It might suggest that the strain-induced band shift leads to the semimetallic
tuning in the SrIrO3 film grown on from SrTiO3 to LSAT substrates. Our findings
illustrate the tunability of SrIrO3 properties and pave the way to induce novel
physical states in SrIrO3 such as the proposed topological insulator state in
heterostructures.
