Quantitative Observation of Threshold Defect Behavior in Memristive Devices with Operando X-ray Microscopy

Huajun Liu, Yongqi Dong, Mathew J. Cherukara, Kiran Sasikumar, Badri Narayanan, Zhonghou Cai, Barry Lai, Liliana Stan, Seungbum Hong, Maria K.Y. Chan, Subramanian K.R.S. Sankaranarayanan, Hua Zhou*, DIllon D. Fong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Memristive devices are an emerging technology that enables both rich interdisciplinary science and novel device functionalities, such as nonvolatile memories and nanoionics-based synaptic electronics. Recent work has shown that the reproducibility and variability of the devices depend sensitively on the defect structures created during electroforming as well as their continued evolution under dynamic electric fields. However, a fundamental principle guiding the material design of defect structures is still lacking due to the difficulty in understanding dynamic defect behavior under different resistance states. Here, we unravel the existence of threshold behavior by studying model, single-crystal devices: resistive switching requires that the pristine oxygen vacancy concentration reside near a critical value. Theoretical calculations show that the threshold oxygen vacancy concentration lies at the boundary for both electronic and atomic phase transitions. Through operando, multimodal X-ray imaging, we show that field tuning of the local oxygen vacancy concentration below or above the threshold value is responsible for switching between different electrical states. These results provide a general strategy for designing functional defect structures around threshold concentrations to create dynamic, field-controlled phases for memristive devices.

Original languageEnglish (US)
Pages (from-to)4938-4945
Number of pages8
JournalACS nano
Issue number5
StatePublished - May 22 2018


  • WO
  • memristive devices
  • operando X-ray imaging
  • quantitative oxygen vacancy profile
  • threshold defect behavior

ASJC Scopus subject areas

  • General Engineering
  • General Physics and Astronomy
  • General Materials Science


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