Article
Physics, Applied
Shiyu He, Baishan Liu, Zhongzheng Pei, Xiaohui Zhang, Bin Liu, Ding-Bang Xiong
Summary: The effect of Stone-Wales, single-vacancy, and double-vacancy defects on the interface properties of copper/graphene/copper sandwich models were investigated using first-principles study. The results showed that most defects forming in the Cu/Gr/Cu interface had lower formation energy than those in the free graphene slab. The introduction of defects enhanced interface bonding while decreasing electrical properties due to electron scattering. Analysis of the differential charge density revealed that the defects caused changes in electron distribution and facilitated charge transfer between graphene and adjacent copper layers by altering the atomic layer distance.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Zhen Tong, Alessandro Pecchia, ChiYung Yam, Traian Dumitrica, Thomas Frauenheim
Summary: The presence of nonhexagonal carbon rings in graphene significantly affects its thermal conductivity, but there are still some dense and ordered arrangements of carbon rings in 2D carbon allotropes that allow thermal energy transfer. The phonon thermal conductivity is lowered while the electron thermal conductivity is enhanced due to the nonhexagonal rings.
ADVANCED ENERGY MATERIALS
(2022)
Article
Physics, Applied
Kashi N. Subedi, Kishor Nepal, Chinonso Ugwumadu, Keerti Kappagantula, D. A. Drabold
Summary: We used density-functional theory (DFT) to investigate the electronic transport properties of copper-graphene (Cu-G) composites. By varying the interfacial distance of copper/graphene/copper (Cu/G/Cu) interface models, we studied the conduction in composites. Our calculations using the Kubo-Greenwood formula showed that the conductivity of the models increased as the Cu-G distance decreased and saturated below a certain threshold. Bader charge analysis based on DFT revealed increasing charge transfer between Cu atoms and graphene as the Cu-G distance decreased. The electronic density of states showed increased contributions from both copper and carbon atoms near the Fermi level with decreasing Cu-G interfacial distance. Space-projected conductivity calculations demonstrated that graphene acted as a bridge for electronic conduction at small Cu-G distances, thus enhancing conductivity.
APPLIED PHYSICS LETTERS
(2023)
Article
Geochemistry & Geophysics
Monica Pozzo, Christopher J. Davies, Dario Alfe
Summary: The thermal conductivity of Earth's core is a critical parameter that affects core cooling rate, inner core age, and geodynamo power. Recent studies have shown a wide range of values for core thermal conductivity due to challenges in extrapolating to core liquid conditions of pressure, temperature, and composition. This study uses density functional theory calculations to determine the thermal conductivity and resistivity of FeSi alloys, and finds that resistivity increases with Si composition and reduces thermal conductivity. Analysis of possible errors in the calculations shows that experimental and corrected calculations are consistent within uncertainties. Core thermal history models based on the corrected estimates of thermal conductivity support previous findings of inner core formation around 400-700 million years ago and an early molten lower mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Chemistry, Physical
Bo Zhang, Zhenyu Wang, Chengxiang Chen, Mengyue Gu, Jun Zhou, Jinying Zhang
Summary: In this study, the electromechanical behavior of violet phosphorene (vP) nanoflakes was investigated experimentally and theoretically. The results showed that vP exhibited different morphologies and properties under different loads and bias voltages. Theoretical analysis based on specific heat capacity and conductivity provided insights into the electromechanical behavior of vP nanoflakes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Xiangyan Luo, Yixin Wang, Zean Tian, Jiajun Ma, Hong Yu, Quan Xie
Summary: This paper explores the stability and physical properties of double-walled carbon nanotubes and the bilayer graphene obtained from their unfolding. It examines the influence of tube diameter and chiral index on the stability and metallization trend of carbon nanotubes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Qian-Rui Huang, Ryunosuke Shishido, Chih-Kai Lin, Chen-Wei Tsai, Jake A. Tan, Asuka Fujii, Jer-Lai Kuo
Summary: The study analyzed the infrared spectra of a series of asymmetric proton-bound dimers with protonated trimethylamine as the proton donor, revealing a red shift in the N-H+ stretching mode frequency as the proton affinity of acceptors increases. Despite the expected pattern, the observed band showed a peculiar splitting of around 300 cm(-1) with intensity resembling a two-level system. Theoretical investigation attributed this band splitting to strong coupling between the proton stretching mode and overtone states of proton bending modes, known as Fermi resonance, providing a general theoretical model linking the strong coupling to a quasi-two-level system intrinsic to proton motions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Optics
I Ghazal, H. Absike, A. Rachadi, H. Ez-Zahraouy
Summary: This study investigated the structural, electronic, optical, and thermoelectric properties of the ACuS(2)(A=Al, Ga, In) ternary chalcopyrite compounds using DFT and Boltzmann transport theory. The results indicate promising applications of these compounds in photovoltaic, optoelectronic, and thermoelectric devices.
Article
Chemistry, Multidisciplinary
Michele Pizzochero, Efthimios Kaxiras
Summary: The addition of hydrogen atom to zigzag graphene nanoribbons (ZGNRs) is investigated, revealing the role of pi-magnetism in governing the chemistry of ZGNRs and the influence of chemisorbed hydrogen atom on the pi-magnetism. The peculiar interplay between chemistry and magnetism is established at the zigzag edges of graphene.
Article
Materials Science, Multidisciplinary
C. N. Kuo, C. C. Chen, C. M. Chang, R. Y. Huang, L. Y. Wang, Y. K. Kuo, C. S. Lue
Summary: The electronic and thermal properties of scandium monoantimonide ScSb were investigated through experimental and theoretical approaches, indicating a low electronic Fermi-level density and semimetallic character in ScSb.
Article
Chemistry, Physical
K. S. Tolstov, B. V. Politov, V. P. Zhukov, E. V. Chulkov, V. L. Kozhevnikov
Summary: Computational modeling in density functional theory was used to simulate the electronic spectra and calculate the structural and energy characteristics of the perovskite oxides Sr2Mg1-xNixMoO6-delta, revealing the impact of oxygen deficiency on electronic properties and the beneficial effects of nickel doping in reducing chemical expansion.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Piotr Ruszala, Maciej J. Winiarski, Malgorzata Samsel-Czekala
Summary: The electronic structures and microscopic electronic properties of novel La1_xTlxN rock-salt materials have been studied. La0.5Tl0.5N exhibits metallic character, while La0.75Tl0.25N is similar to LaSb and LaBi. Topologically non-trivial characteristics are expected in these nitride materials.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Physics, Applied
Ti Xie, Qin Wang, Robert M. Wallace, Cheng Gong
Summary: Graphene sensors show promise in gas detection due to their excellent electrical properties and large surface-to-volume ratio. The response of graphene sensors to NO2 gas depends on the initial doping level, highlighting the importance of graphene conditions in sensor performance.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Raul Alvarado, Nicolas Ramos-Berdullas, Marcos Mandado
Summary: High-level quantum chemical calculations were used to compare the affinity of graphene and white graphene sheets for dioxin-like pollutants, showing that white graphene exhibited a higher adsorption affinity than graphene.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Chemistry, Physical
Juan J. J. Aucar, Alejandro F. F. Maldonado, Juan I. I. Melo
Summary: In this work, relativistic corrections to the electric field gradient (EFG) are presented, including spin-dependent corrections for the first time. The results show that these new corrections significantly improve the performance of the existing method and are in close agreement with calculations at the four-component Dirac-Hartree-Fock (4c-DHF) level. The accuracy of the EFG values obtained with this new method allows for the analysis of the electronic origin of relativistic effects using well-known nonrelativistic operators.
JOURNAL OF CHEMICAL PHYSICS
(2022)