Prediction of nonlayered oxide monolayers as flexible high-κ dielectrics with negative Poisson's ratios.
Nat Commun
; 14(1): 6555, 2023 Oct 17.
Article
em En
| MEDLINE
| ID: mdl-37848484
ABSTRACT
During the last two decades, two-dimensional (2D) materials have been the focus of condensed matter physics and material science due to their promising fundamental properties and (opto-)electronic applications. However, high-κ 2D dielectrics that can be integrated within 2D devices are often missing. Here, we propose nonlayered oxide monolayers with calculated exfoliation energy as low as 0.39 J/m2 stemming from the ionic feature of the metal oxide bonds. We predict 51 easily or potentially exfoliable oxide monolayers, including metals and insulators/semiconductors, with intriguing physical properties such as ultra-high κ values, negative Poisson's ratios and large valley spin splitting. Among them, the most promising dielectric, GeO2, exhibits an auxetic effect, a κ value of 99, and forms type-I heterostructures with MoSe2 and HfSe2, with a band offset of ~1 eV. Our study opens the way for designing nonlayered 2D oxides, offering a platform for studying the rich physics in ultra-thin oxides and their potential applications in future information technologies.
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MEDLINE
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Ano de publicação:
2023
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Article