Hafnia for analog memristor: Influence of stoichiometry and crystalline structure

Fuente: arXiv
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Hauptverfasser: Li, Li-Heng, Xue, Kan-Hao, Yuan, Jun-Hui, Mao, Ge-Qi, Miao, Xiangshui
Format: Preprint
Veröffentlicht: 2022
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author Li, Li-Heng
Xue, Kan-Hao
Yuan, Jun-Hui
Mao, Ge-Qi
Miao, Xiangshui
author_facet Li, Li-Heng
Xue, Kan-Hao
Yuan, Jun-Hui
Mao, Ge-Qi
Miao, Xiangshui
contents The highly non-linear switching behavior of hafnia memristor actually hinders its wide application in neuromorphic computing. Theoretical understanding into its switching mechanism has been focused on the processes of conductive filament generation and rupture, but possible phase transition and crystallization around the region of conductive filaments (CFs) due to the variation of O content have been paid less attention to. In this paper, HfO$\mathrm{_x}$ structural models covering the full stoichiometries from Hf to HfO$\mathrm{_2}$ were established, and the crystal structure evolution during the reduction process of hafnia was obtained through first-principles calculation. The electronic structures and O vacancy migration characteristics of these structures were analyzed. A criterion was prescribed to predict the mode of abrupt binary switching or gradual conductance modulation according to the structure evolution of the CFs. In particular, factors that influence the merging of tiny conductive channels into strong filaments are intensively discussed, including the anisotropy of O vacancy migration and the size effect. The feasibility of Mg doping to achieve robust gradual switching is discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2203_16131
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Hafnia for analog memristor: Influence of stoichiometry and crystalline structure
Li, Li-Heng
Xue, Kan-Hao
Yuan, Jun-Hui
Mao, Ge-Qi
Miao, Xiangshui
Materials Science
The highly non-linear switching behavior of hafnia memristor actually hinders its wide application in neuromorphic computing. Theoretical understanding into its switching mechanism has been focused on the processes of conductive filament generation and rupture, but possible phase transition and crystallization around the region of conductive filaments (CFs) due to the variation of O content have been paid less attention to. In this paper, HfO$\mathrm{_x}$ structural models covering the full stoichiometries from Hf to HfO$\mathrm{_2}$ were established, and the crystal structure evolution during the reduction process of hafnia was obtained through first-principles calculation. The electronic structures and O vacancy migration characteristics of these structures were analyzed. A criterion was prescribed to predict the mode of abrupt binary switching or gradual conductance modulation according to the structure evolution of the CFs. In particular, factors that influence the merging of tiny conductive channels into strong filaments are intensively discussed, including the anisotropy of O vacancy migration and the size effect. The feasibility of Mg doping to achieve robust gradual switching is discussed.
title Hafnia for analog memristor: Influence of stoichiometry and crystalline structure
topic Materials Science
url https://arxiv.org/abs/2203.16131