Ultra-Low Electric Field Induced Volatile Resistive Switching in Hole-Doped MgTi₂O₄

The intriguing concept of electric-field-induced resistive breakdown in Mott insulators offers promising opportunities for Mottronics devices and memristors while serving as a unique platform to explore non-equilibrium phenomena and underlying microscopic mechanisms. However, achieving resistive switching with a low threshold field is rare in transition metal spinel oxides. Here, a reversible resistive breakdown under the application of DC current as well as DC electric-field in hole doped MgTi₂O₄ is reported. A remarkably low threshold field of approximately 60 V/cm at 40 K is observed. Additionally, the resistive transition around 260 K observed in stoichiometric system, is suppressed in Mg-deficient samples. The electric field induced low-resistance state is meta-stable, reverting to the insulating phase once the field is removed, indicating a volatile resistive switching (VRS). Interestingly, these systems demonstrate forming-free, stable threshold switching with minimal cycle-to-cycle variation in switching voltages. Experimental results suggest polaronic hopping and collective charge excitation triggered by applied electric field, with subsequent polaronic filament formation as the driving mechanism for the resistive transition. Further, the neuronal functionalities, particularly the leaky-integrate-fire behavior of an artificial neuron, are showcased in a single-component device using these systems as switching layer, suggesting their potential applicability in low-threshold neuromorphic circuits.