The influence of electron irradiation and the subsequent oxygen adsorption on the electronic structure of an SrTiO3(001) surface was investigated by ultraviolet photoemission spectroscopy (UPS). Electron irradiation induced an in-gap state (IGS) as observed by UPS keeping the surface 1 × 1, which is considered to originate from oxygen vacancies on the topmost surface due to the electron-stimulated desorption (ESD) of oxygen. Electron irradiation also caused a downward shift of the valence band maximum, indicating downward band bending and the formation of a conductive layer on the surface. Adsorption of oxygen on the electron-irradiated surface, on the other hand, reduced the intensity of the IGS along with yielding upward band bending, which points to disappearance of the conductive layer. The results show that ESD and oxygen adsorption can be used to control the surface electronic structure switching between semiconducting and metallic regimes by changing the density of the oxygen vacancies.
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http://dx.doi.org/10.1088/0953-8984/25/16/162202 | DOI Listing |
Adv Sci (Weinh)
January 2025
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India.
Stabilizing large easy-axis type magnetic anisotropy in molecular complexes is a challenging task, yet it is crucial for the development of information storage devices and applications in molecular spintronics. Achieving this requires a deep understanding of electronic structure and the relationships between structure and properties to develop magneto-structural correlations that are currently unexplored in the literature. Herein, a series of five-coordinate distorted square pyramidal Co complexes [Co(L)(X)].
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
The development of stable and tunable polycyclic aromatic compounds (PACs) is crucial for the advancement of organic optoelectronics. Conventional PACs, such as acenes, often suffer from poor stability due to photooxidation and oligomerization, which are linked to their frontier molecular orbital energy levels. To address these limitations, we designed and synthesized a new class of π-expanded indoloindolizines by merging indole and indolizine moieties into a single polycyclic framework.
View Article and Find Full Text PDFJ Taibah Univ Med Sci
December 2024
Universitas Nasional, Department of Biology, South Jakarta, Indonesia.
Objectives: Dementia, a growing concern globally, affects more than 55 million people-a number projected to rise to 152 million by 2050. Current medications target Alzheimer's disease, the most prevalent form of dementia. This study investigated L.
View Article and Find Full Text PDFiScience
January 2025
Department of Artificial Intelligence, Hanyang University, Seoul 04763, South Korea.
We present a Fourier neural operator (FNO)-based surrogate solver for the efficient optimization of wavefronts in tunable metasurface controls. Existing methods, including the Gerchberg-Saxton algorithm and the adjoint optimization, are often computationally demanding due to their iterative processes, which require numerical simulations at each step. Our surrogate solver overcomes this limitation by providing highly accurate gradient estimations with respect to changes in tunable meta-atoms without the need for direct simulations.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Hunan University, Chemistry and Chemical Engineering, Lushan South Road, Yuelu District, 410082, Changsha, CHINA.
Site density and turnover frequency are the two fundamental kinetic descriptors that determine the oxygen reduction activity of iron-nitrogen-carbon (Fe-N-C) catalysts. However, it remains a grand challenge to simultaneously optimize these two parameters in a single Fe-N-C catalyst. Here we show that treating a typical Fe-N-C catalyst with ammonium iodine (NH4I) vapor via a one-step chemical vapor deposition process not only increases the surface area and porosity of the catalyst (and thus enhanced exposure of active sites) via the etching effect of the in-situ released NH3, but also regulates the electronic structure of the Fe-N4 moieties by the iodine dopants incorporated into the carbon matrix.
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