Examining the weak localization and weak anti-localization in correlated semimetallic SrIrO$_{\mathrm{3}}$ thin films

We have studied the weak localization (WL) and weak anti-localization (WAL) effects in epitaxial SrIrO$_{\mathrm{3}}$ (SIO) thin films to probe the electron correlation and spin-orbit coupling (SOC). We deposited 2-30 nm SIO thin films on SrTiO$_{\mathrm{3}}$ (001) substrates via off-axis RF magnetron sputtering, with c-axis (pseudo-cubic) growth and atomically smooth surfaces achieved. Resistance of the films shows a moderate decrease with decreasing temperature. Modeling the Hall effect result with the two-carrier model and assuming equal electron- and hole-densities, we extracted a carrier density of \textasciitilde 10$^{\mathrm{20}}$ cm$^{\mathrm{-3}}$ and comparable electron and hole mobility of \textasciitilde 50 cm$^{\mathrm{2}}$/Vs. For films below 5 nm, we observed a slight resistance upturn at low temperature, which can be attributed to WL. The low temperature magnetoconductance (MC) (2-15 K) shows a transition from WAL to WL. By fitting the MC with the Maekawa-Fukuyama model, we extracted the inelastic dephasing time and spin relaxation time. While the inelastic field shows linear temperature dependence, suggesting electron-electron interaction as the phase breaking mechanism, the spin relaxation field exhibits quadratic temperature dependence. We also explore the effect of carrier doping on the spin relaxation time using the electric field effect approach.