Direct observation of metal-insulator transition in single-crystalline germanium telluride nanowire memory devices prior to amorphization. Academic Article uri icon

abstract

  • Structural defects and their dynamics play an important role in controlling the behavior of phase-change materials (PCM) used in low-power nonvolatile memory devices. However, not much is known about the influence of disorder on the electronic properties of crystalline PCM prior to a structural phase-change. Here, we show that the application of voltage pulses to single-crystalline GeTe nanowire memory devices introduces structural disorder in the form of dislocations and antiphase boundaries (APB). The dynamic evolution and pile-up of APBs increases disorder at a local region of the nanowire, which electronically transforms it from a metal to a dirty metal to an insulator, while still retaining single-crystalline long-range order. We also observe that close to this metal-insulator transition, precise control over the applied voltage is required to create an insulating state; otherwise the system ends up in a more disordered amorphous phase suggesting the role of electronic instabilities during the structural phase-change.

published proceedings

  • Nano Lett

author list (cited authors)

  • Nukala, P., Agarwal, R., Qian, X., Jang, M. H., Dhara, S., Kumar, K., ... Agarwal, R

citation count

  • 56

complete list of authors

  • Nukala, Pavan||Agarwal, Rahul||Qian, Xiaofeng||Jang, Moon Hyung||Dhara, Sajal||Kumar, Karthik||Johnson, AT Charlie||Li, Ju||Agarwal, Ritesh

publication date

  • March 2014