Simulation of atomic redistribution in Ge-Sb-Te (GST)-based memory cells during SET/RESET cycling is needed in order to understand GST memory cell failure and to design improved non-volatile memories. However, this type of atomic scale simulations is extremely challenging. In this work, we propose to use a simplified GST system in order to catch the basics of atomic redistribution in Ge-rich GST (GrGST) films using atomistic kinetic Monte Carlo simulations. Comparison between experiments and simulations shows good agreements regarding the influence of Ge excess on GrGST crystallization, as well as concerning the GST growth kinetic in GrGST films, suggesting the crystallized GST ternary compound to be off-stoichiometric. According to the simulation of atomic redistribution in GrGST films during SET/RESET cycling, the film microstructure stabilized during cycling is significantly dependent of the GST ternary phase stoichiometry. The use of amorphous layers exhibiting the GST ternary phase stoichiometry placed at the bottom or at the top of the GrGST layer is shown to be a way of controlling the microstructure evolution of the film during cycling. The significant evolution of the local composition in the amorphous solution during cycling suggests a non-negligible variation of the crystallization temperature with operation time.
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http://dx.doi.org/10.1088/1361-6528/ac6813 | DOI Listing |
We study resonance redistribution mechanisms inside a hot vapor cell. This is achieved by pumping cesium atoms on the 6S→6P resonance and subsequently probing the velocity distribution of the 6P population by a linear absorption experiment on the 6P→16S or 6P→15D transitions at 514 nm and 512 nm, respectively. We demonstrate that despite the existence of thermalization processes, traces of the initial velocity selection, imposed by the pump, survive in hyperfine levels of the intermediate (6P) state.
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January 2025
Key Laboratory of Optoelectronic Sensing and Intelligent Control, Hubei University of Science and Technology, Xianning, 437100, China.
We present a novel approach to realize three-dimensional (3D) matter wave solitons (MWSs) transformation between different optical potential wells by manipulating their depths and centers. The 3D MWSs are obtained by the square operator method, and transformed to other types (elliptical/ring/necklace) by performing time evolution with the split-step Fourier method. The effectiveness and reliability of our approach is demonstrated by comparing the transformed solitons with those obtained iteratively using the square operator method.
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January 2025
Institute of Molecular Metrology, College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, P. R. China.
The elementary mechanism and site studies of nanozyme-based inhibition reactions are ambiguous and urgently require advanced nanozymes as mediators to elucidate the inhibition effect. To this end, we develop a class of nanozymes featuring single Cu-N catalytic configurations and B-O sites as binding configurations on a porous nitrogen-doped carbon substrate (B/Cu) for inducing modulable inhibition transfer at the atomic level. The full redistribution of electrons across the Cu-N sites, induced by B-O sites incorporation, yields B/Cu with enhanced peroxidase-like activity versus Cu.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China.
In the study of GaN/AlGaN heterostructure thermal transport, the interference of strain on carriers cannot be ignored. Although existing research has mainly focused on the intrinsic electronic and phonon behavior of the materials, there is a lack of studies on the transport characteristics of the electron-phonon coupling in heterostructures under strain control. This research comprehensively applies first-principles calculations and the Boltzmann transport equation simulation method to deeply analyze the thermal transport mechanism of the GaN/AlGaN heterojunction considering in-plane strain, with particular attention to the regulatory role of electron-phonon coupling on thermal transport.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Research Laboratory Neuroelectronics and Memristive Nanomaterials (NEUROMENA Lab), Institute of Nanotechnologies, Electronics and Electronic Equipment Engineering, Southern Federal University, Taganrog 347922, Russia.
This paper presents the results of a study on the formation of nanostructures of electrochemical titanium oxide for neuromorphic applications. Three anodization synthesis techniques were considered to allow the formation of structures with different sizes and productivity: nanodot, lateral, and imprint. The mathematical model allowed us to calculate the processes of oxygen ion transfer to the reaction zone; the growth of the nanostructure due to the oxidation of the titanium film; and the formation of TiO, TiO, and TiO oxides in the volume of the growing nanostructure and the redistribution of oxygen vacancies and conduction channel.
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