Structural study of active layer lithium niobium (III) oxide-LiNbO₂memristors

Memristors are a key element in developing a brain inspired neuromorphic computing system that offers a promising platform to overcome the von Neumann bottleneck. Recently, lithium niobite (Li_xNbO₂) has been shown to be a promising candidate for the memristor, where changing the lithium content enables precise control of the resistive states. While previous work has demonstrated the correlation between the lithium concentration and the increase of metallic response in Li_xNbO₂ via the density functional theory and x-ray photoelectron spectroscopy, a direct view of the structural variations from the delithiation and their effects on the resistivity switch remains unknown. Here, we used Raman spectroscopy to study the nature of Li_xNbO2 memristors by probing the structure as delithiation takes place. Raman spectra are measured for both pristine and chemically delithiated Li_xNbO₂ crystals. We find two main peaks related to Li E_2g and O A_1g modes that can be used to track the local structural modifications related to the change in lithium concentration. The spectral signatures will provide essential insights on the Li- intercalation based switching mechanism in active layer Li_xNbO₂ memristors.