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Research Article
Ab-initio Study on Gold Doped Graphene
Nigatu Desalegn*,
Tamirat Yibika,
Takele Teshome Somano
Issue:
Volume 10, Issue 1, March 2025
Pages:
1-20
Received:
31 August 2024
Accepted:
7 December 2024
Published:
17 January 2025
DOI:
10.11648/j.wjap.20251001.11
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Abstract: This thesis investigates the electronic structure of gold-doped Graphene using first-principles calculations based on density functional theory (DFT). Employing a plane wave pseudo potential approach, the research applies generalized gradient approximations (GGA) for the exchange-correlation potential. Geometry optimization was included in all calculations to ensure complete structural relaxation, enhancing the robustness of the results. A detailed analysis was conducted to establish convergence concerning kinetic energy cutoff and k-point mesh size. Graphene showed convergence at 30 Ray, allowing for reduced computational costs, and a uniform k-point mesh of 8 × 8 × 1 was used, yielding accurate charge density and a lattice constant of 2.476 Å. Notably, the band structure reveals that two bands intersect at the K-point, indicating unique zero-gap electronic characteristics in both pure and Au-doped Graphene, which exhibit semiconductor behavior with a minimal band gap linked to the gold atom. The density of states (DOS) plot confirms no overlap at the Fermi energy or a band gap between the valence and conduction bands, solidifying grapheme’s semiconducting nature. The band crossing at the Fermi level in the Au-doped Graphene super cell is particularly important, showing that the Fermi level shifts into the conduction band, with a notable DOS peak at the Fermi level indicative of strong interactions between the Au dopant and the Graphene matrix. Consequently, gold doping effectively alters the electronic properties of Graphene, rendering it semi-metallic. These findings contribute significantly to the fields of materials science and electronic applications.
Abstract: This thesis investigates the electronic structure of gold-doped Graphene using first-principles calculations based on density functional theory (DFT). Employing a plane wave pseudo potential approach, the research applies generalized gradient approximations (GGA) for the exchange-correlation potential. Geometry optimization was included in all calc...
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Research Article
The Mechanical Properties of Waves and Their Application
Takele Teshome Somano*
Issue:
Volume 10, Issue 1, March 2025
Pages:
21-27
Received:
2 January 2025
Accepted:
20 January 2025
Published:
11 February 2025
DOI:
10.11648/j.wjap.20251001.12
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Views:
Abstract: This study explores the captivating world of waves, focusing on their fundamental properties and diverse applications. At its core, a wave is a disturbance that propagates through a medium, transferring energy without permanently displacing the medium's particles. These disturbances can manifest in various forms, including changes in shape, pressure, the strength of electric or magnetic fields, electric potential, or even temperature. The magnitude of a wave is determined by its amplitude, with smaller amplitudes indicating smaller waves and larger amplitudes signifying more substantial ones. The wave's frequency, or the rate at which it oscillates, dictates its temporal behavior; lower frequencies correspond to slower wave motion. Notably, there is an inverse relationship between frequency and wavelength: as frequency increases, wavelength decreases proportionally. A common example of wave behavior is the visible light portion of the electromagnetic spectrum, where energy is carried in discrete packets called photons. Irrespective of type, waves invariably act as channels for energy transmission. Importantly, waves do not transport the medium itself; rather, they propagate through it, causing localized vibrations or oscillations as they serve as conduits for energy, rather than bulk movement of matter. In essence, a wave is initiated by a disturbance at its source, generating a pattern of oscillations that radiate outward, creating the impression of a traveling wave. By understanding these fundamental principles, we can unlock the potential of wave phenomena across a wide range of scientific and technological disciplines.
Abstract: This study explores the captivating world of waves, focusing on their fundamental properties and diverse applications. At its core, a wave is a disturbance that propagates through a medium, transferring energy without permanently displacing the medium's particles. These disturbances can manifest in various forms, including changes in shape, pressur...
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Research Article
Atomic and Molecular Physics in Astrophysics: Probing the Universe Through Spectroscopic Techniques
Diriba Gonfa Tolasa*
Issue:
Volume 10, Issue 1, March 2025
Pages:
28-34
Received:
3 January 2025
Accepted:
18 January 2025
Published:
11 February 2025
DOI:
10.11648/j.wjap.20251001.13
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Views:
Abstract: The interplay between atomic and molecular physics and astrophysics is critical for advancing the understanding of the universe. This paper investigates the significance of spectroscopic techniques in probing celestial phenomena, emphasizing their role in revealing the composition, temperature, density, and motion of astronomical objects. By analyzing the spectral lines emitted or absorbed by various elements and molecules, researchers can derive essential insights into the physical conditions prevailing in stars, galaxies, and interstellar media. Recent advancements in high-resolution spectroscopy and the deployment of space-based observatories have significantly enhanced our observational capabilities. High-resolution spectroscopy, facilitated by state of the art instruments such as the Keck Observatory and the Very Large Telescope (VLT), has enabled the detection of faint spectral lines and complex molecular interactions. Additionally, infrared and ultraviolet spectroscopy has proven invaluable for studying cooler celestial objects and high-energy phenomena, respectively, further enriching our understanding of cosmic processes. This article also reviews key findings from contemporary research, including the detection of heavy elements in stellar atmospheres and the identification of molecular signatures in exoplanet atmospheres. Such findings not only inform us about the evolutionary processes governing stellar life cycles but also suggest that the building blocks of life may be widespread throughout the universe. Moreover, the implications of these discoveries for cosmology and the search for extraterrestrial life are explored, highlighting the vital role that atomic and molecular physics plays in shaping our comprehension of the cosmos. As continue to refine the spectroscopic methodologies and expand our observational reach, this research underscores the importance of integrating atomic and molecular physics with astrophysical observations. The potential for groundbreaking discoveries remains vast, paving the way for new avenues of inquiry in astrophysics and cosmology. Ultimately, this paper aims to illuminate the intricate relationships between the fundamental building blocks of matter and the cosmic phenomena that define our existence, fostering a deeper appreciation for the complexities of the universe we inhabit.
Abstract: The interplay between atomic and molecular physics and astrophysics is critical for advancing the understanding of the universe. This paper investigates the significance of spectroscopic techniques in probing celestial phenomena, emphasizing their role in revealing the composition, temperature, density, and motion of astronomical objects. By analyz...
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