Electrically tunable transport in antiferromagnetic Sr $_{\mathrm{\mathbf{3}}}$\textbf{Ir}$_{\mathrm{\mathbf{2}}}$\textbf{O}$_{\mathrm{\mathbf{7}}}$

Recently we demonstrated experimentally the existence of interconnections between magnetic state and transport currents in antiferromagnetic (AFM) Mott insulator Sr$_{\mathrm{2}}$IrO$_{\mathrm{4}}$. We found a very large anisotropic magnetoresistance [1] and demonstrated a reversible resistive switching driven by high-density currents/high electric fields [2]. These results support the feasibility of AFM spintronics, where antiferromagnets are used in place of ferromagnets, however a low N\'{e}el temperature of this material (240 K) questions any practical applications. Here we present a comparative electrical transport study of its sister compound Sr$_{\mathrm{2}}$IrO$_{\mathrm{4}}$ which has a higher transition temperature (285 K). Similar to the case of Sr$_{\mathrm{2}}$IrO$_{\mathrm{4}}$, we find a continuous reduction in the resistivity of Sr$_{\mathrm{3}}$Ir$_{\mathrm{2}}$O$_{\mathrm{7}}$ as a function of increasing electrical bias and abrupt reversible changes above a threshold bias current. We explain these results by a reduction of activation energy associated with a field-driven lattice distortion. [1] C. Wang et al., Phys. Rev. X 4, 041034 (2014); [2] C. Wang et al, PRB 92, 115136 (2015).