Achieving Forming-Free NbO_<i>x</i> Mott Memristors With High Performance Through Lithium Intercalation

In recent years, niobium oxide (NbO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub>)-based Mott memristors have attracted considerable attention due to their promising applications in neuromorphic computing. However, the relatively high voltages required for the electroforming process pose a significant challenge to their large-scale integration. To address this issue, in this work, a thin layer of lithium titanate (Li<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>4</roman></sub>Ti<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>5</roman></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>12</roman></sub>, LTO) is introduced to intercalate lithium ions into the NbO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> switching layer within a device structured as Pt/LTO/Nb/ NbO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub>/W/Ti, successfully achieving a forming-free NbO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> Mott memristor. This modification not only enables the forming-free operation but also results in a marked reduction in the threshold current, lowering it to 19 μA, a sig-nificant improvement compared to >100 μA observed in the control sample without the intercalated layer, thereby substantially reducing energy consumption. Moreover, the composition and migration of Li<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ions are elucidated through electron energy loss spectroscopy (EELS). Finally, to demonstrate the practical application of these forming-free memristors, an oscillation circuit is constructed to demonstrate its potential application in artificial neurons.