This title appears in the Scientific Report :
2018
Please use the identifier:
http://hdl.handle.net/2128/20756 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevMaterials.2.115002 in citations.
Routes for increasing endurance and retention in HfO 2 -based resistive switching memories
Routes for increasing endurance and retention in HfO 2 -based resistive switching memories
We investigate metastable and thermodynamically stable phases that can be expected to occur in electroformed filaments in resistively switching hafnia, and discuss their relevance for the switching process. To this end, we conduct a study, based on density functional theory combined with an evolutio...
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Personal Name(s): | Rushchanskii, Konstantin (Corresponding author) |
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Blügel, Stefan / Ležaić, Marjana | |
Contributing Institute: |
Quanten-Theorie der Materialien; IAS-1 JARA - HPC; JARA-HPC JARA-FIT; JARA-FIT Quanten-Theorie der Materialien; PGI-1 |
Published in: | Physical review materials, 2 (2018) 11, S. 115002 |
Imprint: |
College Park, MD
APS
2018
|
DOI: |
10.1103/PhysRevMaterials.2.115002 |
Document Type: |
Journal Article |
Research Program: |
Ab initio study of novel multiferroic materials Controlling Configuration-Based Phenomena Controlling Spin-Based Phenomena |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevMaterials.2.115002 in citations.
We investigate metastable and thermodynamically stable phases that can be expected to occur in electroformed filaments in resistively switching hafnia, and discuss their relevance for the switching process. To this end, we conduct a study, based on density functional theory combined with an evolutionary algorithm determining the composition-dependent (meta)stable phases in HfOx, focusing on the region 0<x<2. We find that oxygen vacancies in hafnia tend to form regular patterns, which leads to periodic metastable structures featuring one-dimensional open channels, thus favoring ionic conductivity in the host material, i.e., oxygen migration. The band gap of such structures is systematically lowered with increasing oxygen deficiency, resulting in metallic behavior when oxygen migrates out of the channels. Moreover, we find that the solubility of oxygen in metallic Hf is very high, up to one oxygen per six metallic atoms, the concentration corresponding to a thermodynamically stable and ordered metallic compound, Hf6O. Therefore, thick enough metallic capping of Hf could play the role of an active electrode for hosting oxygen which migrates out of HfO2. In combination with reversible oxygen migration in predicted suboxide phases, this should lead to robust resistive memory cells with high endurance and long retention. |