Physical origins of current and temperature controlled negative differential resistances in NbO2. Academic Article uri icon


  • Negative differential resistance behavior in oxide memristors, especially those using NbO2, is gaining renewed interest because of its potential utility in neuromorphic computing. However, there has been a decade-long controversy over whether the negative differential resistance is caused by a relatively low-temperature non-linear transport mechanism or a high-temperature Mott transition. Resolving this issue will enable consistent and robust predictive modeling of this phenomenon for different applications. Here we examine NbO2 memristors that exhibit both a current-controlled and a temperature-controlled negative differential resistance. Through thermal and chemical spectromicroscopy and numerical simulations, we confirm that the former is caused by a ~400K non-linear-transport-driven instability and the latter is caused by the ~1000K Mott metal-insulator transition, for which the thermal conductance counter-intuitively decreases in the metallic state relative to the insulating state.The development of future computation devices will be aided by a better understanding of the physics underlying material behaviors. Using thermoreflectance and spatially resolved X-ray microscopy, Kumar et al. elucidate the origin of two types of negative differential resistance in NbO2 memristors.

published proceedings

  • Nat Commun

altmetric score

  • 0.75

author list (cited authors)

  • Kumar, S., Wang, Z., Davila, N., Kumari, N., Norris, K. J., Huang, X., ... Williams, R. S.

citation count

  • 98

complete list of authors

  • Kumar, Suhas||Wang, Ziwen||Davila, Noraica||Kumari, Niru||Norris, Kate J||Huang, Xiaopeng||Strachan, John Paul||Vine, David||Kilcoyne, AL David||Nishi, Yoshio||Williams, R Stanley

publication date

  • September 2017