Current-voltage characteristics in single layer SrIrO₃films deposited on LaAlO₃(100) substrate

Here, we investigate the structural and electrical properties on SrIrO₃films grown on LaAlO₃(100) substrate with varying thickness (18, 25 and 40 nm). The x-ray diffraction shows good quality epitaxial films without any chemical impurity. The out-of-plane lattice parameter increases with the film thickness. All the films show a semiconducting behavior where the resistivity increases with increasing thickness. Our analysis shows at high temperature the charge conduction mechanism follows Mott's two-dimensional variable-range-hopping model. Detailed current-voltage (I-V) measurements show a linear Ohmic behavior at room temperature, however, a prominent deviation from linearity has been observed at low temperatures where the exponentn(I∝Vn) increases with decreasing temperature, reachingn ∼1.5 at low temperature. Analysis ofI-Vdata indicates that the charge conduction has dominant contribution of Poole-Frenkel mechanism rather than Schottky behavior. This evolution of charge transport with temperature is quite intriguing which may be related to the development of low temperature magnetism in films of SrIrO₃.