Physical model of threshold switching in NbO2 based memristors

This paper investigates the origin of the threshold switching effect in NbO2. It is found that the effect is independent of the metal-insulator-transition but can be explained by a trap-assisted Frenkel-Poole like conduction mechanism in combination with a moderate temperature increase by only 150 K due to Joule heating. These findings lead to the development of a physics based model which is of pure electrical nature and explains the occurrence of the threshold effect as well as the negative-differential resistance behavior observed in NbO2.