Current–voltage characteristics in single layer SrIrO₃ films deposited on LaAlO₃(100) substrate

Abstract

Here, we investigate the structural and electrical properties on SrIrO3 films 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 exponent n ( I ∝ V n ) increases with decreasing temperature, reaching n ∼ 1.5 at low temperature. Analysis of I–V data 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.

Tunable charge transport properties in non-stoichiometric SrIrO3 thin films

“…Using the relation given in equation ( 2), considering the obtained N (E F ) value, the localization length for S1, S2 and S3 samples are calculated (table 2). Confirming the strain-induced WL effects on SIO films grown on STO substrates [42] (table 2). As the disorder increases, the T 0 value increases, which results in a decrease in the localization length, which indicates an increase in disorder in the system.…”