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Tracking the Movement of Dopants in an Analog Memristor Using X-Ray Absorption Spectroscopy

Jordan Greenlee, James Compagnoni, Cole Petersburg, Faisal Alamgir, W. Alan Doolittle

1) Department of Electrical and Computer Engineering, Georgia Tech 2) Department of Materials Science and Engineering, Georgia Tech

Normalized X-ray Absorption Spectroscopy (XAS) of an as-grown (blue) and 2.0 V biased (green) LiNbO2 memristor. Five regions are collected across the device where the spectra labeled “1” is closest to the positively biased contact and the spectra labeled “5” is closest to the grounded contact of the device.

Schematic density of states for a layered trigonal prismatic semiconductor (left), LiNbO2. The states above the Fermi level are probed using XAS and change as lithium dopants are redistributed across an LiNbO2 memristor under the application of a bias.

Analog memristors based on semiconducting LiNbO2 have been characterized using X-ray Absorption Spectroscopy (XAS). We have identified the underlying analog memristance mechanism as the gradual movement of lithium in the device in response to an applied bias. By identifying the physical memristance mechanism in analog LiNbO2 memristors, device modifications including the use of an electrolyte have been identified to vary the memory permanence of the device.