Anomalous pressure dependence of the electronic transport and anisotropy in SrIrO₃ films

Iridate oxides display exotic physical properties that arise from the interplay between a large
spin-orbit coupling and electron correlations. Here, we present a comprehensive study of the
effects of hydrostatic pressure on the electronic transport properties of SrIrO3 (SIO), a system
that has recently attracted a lot of attention as potential correlated Dirac semimetal. Our
investigations on untwinned thin films of SIO reveal that the electrical resistivity of this material
is intrinsically anisotropic and controlled by the orthorhombic distortion of the perovskite unit
cell. These effects provide another evidence for the strong coupling between the electronic and
lattice degrees of freedom in this class of compounds. Upon increasing pressure, a systematic
increase of the transport anisotropies is observed. The anomalous pressure-induced changes of
the resistivity cannot be accounted for by the pressure dependence of the density of the electron
charge carriers, as inferred from Hall effect measurements. Moreover, pressure-induced
rotations of the IrO6 octahedra likely occur within the distorted perovskite unit cell and affect
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electron mobility of this system.