Article
Chemistry, Physical
Ramiz Zulkharnay, Neil L. Allan, Paul W. May
Summary: Surface modification of diamond with the addition of metals or other electropositive adsorbates can result in negative electron affinity (NEA). Scandium adsorption on diamond is energetically favorable, especially on the oxygenated surface. Most stable scandium adsorption configurations possess NEA, with the highest NEA value found on the oxygenated diamond surface.
Article
Chemistry, Physical
Debadutta Prusty, Alejandro Gallegos, Jianzhong Wu
Summary: The interfacial behavior of associating species is crucial for both fundamental physics and industrial applications. This study investigates the adsorption behavior of a mixture of nanoparticles and polymer chains, representing asphaltene and resin molecules, onto an attractive surface. The results provide insights into the effects of various characteristics of these molecules on the adsorption amount and reveal the interplay between different driving forces.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Physical
Sami Ullah, Gary Wan, Christos Kouzios, Cameron Woodgate, Mattia Cattelan, Neil Fox
Summary: Wideband gap diamond-based materials are being studied for energy harvesting and quantum applications, with Sn identified as a potential candidate for negative electron affinity on diamond surfaces. Experimental results show that SnO termination on diamond surfaces can lead to NEA and reduce the work function, making it a stable option for device applications. The intercalation of Li with SnO planes enhances the stability of LiO termination on diamond surfaces and reduces the work function even further, showing potential for more efficient diamond surface terminations.
APPLIED SURFACE SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Chenxi Li, Eliezer F. Oliveira, Abhijit Biswas, Anand B. Puthirath, Xiang Zhang, Atin Pramanik, Elias J. Garratt, Mahesh R. Neupane, Bradford B. Pate, Anthony Glen Birdwell, Tony G. Ivanov, Tanguy Terlier, Robert Vajtai, Pulickel M. Ajayan
Summary: Diamond surface functionalization has attracted significant research interest, particularly H-termination due to its ability to enhance surface conductivity. This study focused on exploring the attachment of different functional groups, such as nitrogen and sulfur heteroatoms, on the diamond surface and their impact on electronic structure. The functionalized diamond surfaces were found to possess higher conductivity than H-terminated diamonds and showed a downshift in the conduction band minimum and valence band maximum, indicating a reduced bandgap. These findings suggest the potential of heteroatom functionalizations on diamond surfaces for various electronic applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Yu Yang, Franz A. Koeck, Xingye Wang, Robert J. Nemanich
Summary: A thin layer of Al2O3 was used as an interface layer to increase the hole mobility of diamond, reduce Coulomb scattering, and improve material performance.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Zhaolong Sun, Gao Nan
Summary: The structural and electronic properties of boron and nitrogen coterminated diamond surface with various B/N ratios were investigated. The results showed that the diamond surface characteristics changed with increasing B/N ratio and B and N related surface states were introduced into the bandgap region of bulk diamond.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Engineering, Mechanical
Hyeontaek Oh, Euihyun Jo, Hye Woon Jang, Hyeongjun Jung, Sang Hyeok Park, A. Young Kim, Jong Hoon Jung, Ji Ho Youk, Minbaek Lee
Summary: A hard coating material was synthesized to enhance the electrical and mechanical properties of TENGs. This hard coating material exhibited superior performance in a large-scale demonstration.
EXTREME MECHANICS LETTERS
(2022)
Article
Chemistry, Physical
Egor Ukraintsev, Alexander Kromka, Wiebke Janssen, Ken Haenen, Daisuke Takeuchi, Petr Babor, Bohuslav Rezek
Summary: By surface treatment using electrochemically grown polypyrrole, the secondary-electron emission and photoelectron emission from boron-doped diamond are enhanced, surpassing the electron emission intensity from the hydrogen-terminated surface with negative electron affinity. This enhancement is stable for at least one month in air and persists in vacuum even after thermal annealing.
Article
Materials Science, Multidisciplinary
Junaid Khan, Shah Khalid, Waqar Uddin, Rabah Khenata, Maaz Khan, Shafiq Ur Rehman, Munir Ahmad, Shuangxi Wang, Wenqi Huang, S. Bin Omran, Muhammad Fawad
Summary: Using first-principles calculations, this study predicted different structures of lithium atoms with solid electrolytes and their coordination number for the first time. The unique coordination of lithium atoms with ethylene carbonate was explored, showing that only one type of lithium coordinates with EC molecules. The coordination number of EC molecules increases with decreasing minimization or optimization energy and the charge of lithium ions.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Biochemistry & Molecular Biology
Prabhat Ranjan, Brotati Chakraborty, Tanmoy Chakraborty
Summary: A detailed computational analysis is carried out for various acridine derivatives using conceptual density functional theory (CDFT). The study reveals that these compounds exhibit pronounced electron acceptor behavior in the excited state, and acridone has the highest HOMO-LUMO energy gap, indicating the feasibility of one-way electron transfer.
MOLECULAR DIVERSITY
(2023)
Article
Chemistry, Physical
Diptarka Hait, Yu Hsuan Liang, Martin Head-Gordon
Summary: This study explores the prediction of molecular multipole moments and the assessment of performance in describing molecular interactions with external electric fields within density functional theory. The use of translationally invariant second cumulants matrix shows better performance, while some modern functionals may exhibit disappointing results.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Zhaolong Sun, Bo Cui, Pingping Liang, Qimeng Liu, Nan Gao, Hongdong Li
Summary: This study explores the potential of hafnium (Hf) terminated diamond surfaces in achieving negative electron affinity (NEA). By using swarm-intelligence structural search and first-principles calculations, the researchers found that Hf-terminated diamond surfaces exhibit stable NEA properties and high thermal stability, making them promising candidate materials for electron emission applications.
DIAMOND AND RELATED MATERIALS
(2024)
Article
Chemistry, Physical
Pengfei Qiao, Kang Liu, Sen Zhang, Zhenhua Su, Bing Dai, Jiecai Han, Jiaqi Zhu
Summary: The energy band diagram of the Si-treated diamond surface was investigated experimentally, which showed similarities to a hydrogen-terminated surface. This may be the origin of the reported C-Si diamond two-dimensional hole gas channel.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
John Isaac Enriquez, Fahdzi Muttaqien, Masato Michiuchi, Kouji Inagaki, Masaaki Geshi, Ikutaro Hamada, Yoshitada Morikawa
Summary: A study of diamond oxidation mechanism revealed that oxygen adsorption causes C-dimer bond breaking, with the formation of ether chains at higher surface coverage. CO desorption creates point defects that determine preferred etching direction and surface reconstruction. The research provides insights into the atomic-level processes involved in diamond oxidative etching.
Article
Chemistry, Physical
Donghyeon Kang, Hyeon Yeong Lee, Joon-Ha Hwang, Sera Jeon, Dabin Kim, SeongMin Kim, Sang-Woo Kim
Summary: This study investigated the impact of molecular structure deformation on the triboelectric properties of PTFE induced by contact force using density functional theory (DFT). The results showed that deformation enhanced the negative triboelectric property of PTFE mainly due to the electron-deficient state of carbon atoms leading to enhanced local dipole.
Article
Chemistry, Physical
Sergio Conejeros, M. Zamir Othman, Alex Croot, Judy N. Hart, Kane M. O'Donnell, Paul W. May, Neil L. Allan
Summary: This study reports the energetics and electronic properties of Li and N co-doped diamond, with emphasis on the behavior of LiCN4 clusters as potential shallow donors. The results suggest that substitutional Li, when combined with N, may stabilize the LiCN4 cluster to exhibit shallow donor behavior.
Article
Chemistry, Physical
Harry W. T. Morgan, Harry J. Stroud, Neil L. Allan
Summary: The study reveals that hydride ion conductivity is closely related to hydride-oxide disorder, and the diffusion rate of hydride ions is affected by a reduction in A-site cation size. Pressure can change the dominant migration pathway, while the local structural flexibility along migration pathways is determined by dimensionality and ionic size.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Mat Tolladay, Fabrizio Scarpa, Neil L. Allan
Summary: Different computational methods were compared to determine the force between carbon atoms and their ability to accurately simulate carbon-carbon bonds breaking due to mechanical strain. DFTB3 was found to give results similar to first-principles methods, highlighting the importance of electronic behavior for determining the mechanical strength of materials at atomic-length scales.
Article
Multidisciplinary Sciences
Joshua Jenkins, Mohd I. Ishak, Marcus Eales, Ali Gholinia, Satishkumar Kulkarni, Thomas F. Keller, Paul W. May, Angela H. Nobbs, Bo Su
Summary: In order to robustly assess the antibacterial mechanisms of nanotopographies, it is critical to analyze the bacteria-nanotopography adhesion interface. Three-dimensional reconstructions of Staphylococcus aureus or Escherichia coli interacting with nanotopographies were generated using focused ion beam milling combined with scanning electron microscopy. The 3D morphometric analysis quantified the intrinsic contact area between each nanostructure and the bacterial envelope, providing an objective framework for deriving possible antibacterial mechanisms.
Article
Geochemistry & Geophysics
Karen Valencia, Aldemar De Moya, Guillaume Morard, Neil L. Allan, Carlos Pinilla
Summary: In this study, density functional theory calculations were used to determine the electronic structure, acoustic, and thermal properties of Fe3S at high pressures. The results showed a magnetic transition from ferromagnetic to non-magnetic state at high pressures, leading to changes in the physical properties of Fe3S. The thermal expansion, heat capacity, and other parameters were also estimated at high pressures. The possible implications of these findings for the Earth's inner core and the core-mantle boundary of Mars were discussed.
AMERICAN MINERALOGIST
(2022)
Article
Multidisciplinary Sciences
Harry J. Stroud, Chris E. Mohn, Jean-Alexis Hernandez, Neil L. Allan
Summary: The energy landscape and diffusion mechanism of the fast-ion conductor Bi4V2O11 were studied using density functional theory and ab initio molecular dynamics. It was found that diffusion mainly occurs in the vanadium layers in the 110 directions, involving cooperative motion of oxide ions between specific sites. The calculated ionic conductivity was in reasonable agreement with experimental results.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Multidisciplinary Sciences
Chris E. Mohn, Marcin Krynski, Walter Kob, Neil L. Allan
Summary: The study reveals that fluoride diffusion is highly collective, forming dynamic Frenkel defects and collective chains.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Chemistry, Physical
Neil L. Allan, Sergio Conejeros, Judy N. Hart, Chris E. Mohn
Summary: The energy landscape concept is increasingly valuable in understanding and unifying the structural, thermodynamic, and dynamic properties of inorganic solids, highlighting the importance of local structural environments over average structure considerations.
THEORETICAL CHEMISTRY ACCOUNTS
(2021)
Article
Chemistry, Multidisciplinary
Markos Poulos, Stefanos Giaremis, Joseph Kioseoglou, John Arvanitidis, Dimitris Christofilos, Sotirios Ves, Markus P. Hehlen, Neil L. Allan, Chris E. Mohn, Konstantinos Papagelis
Summary: Inelastic neutron scattering measurements of Y3Al5O12 were presented, with comparison of neutron-weighted phonon density-of-states and optical phonon frequencies to atomistic calculations within the Quasi-Harmonic Approximation. The phonon-related thermodynamic and elastic properties calculated within the QHA showed excellent agreement with experimental data.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Chemistry, Physical
Ramiz Zulkharnay, Neil L. Allan, Paul W. May
Summary: Surface modification of diamond with the addition of metals or other electropositive adsorbates can result in negative electron affinity (NEA). Scandium adsorption on diamond is energetically favorable, especially on the oxygenated surface. Most stable scandium adsorption configurations possess NEA, with the highest NEA value found on the oxygenated diamond surface.
Article
Chemistry, Multidisciplinary
Gufei Zhang, Ramiz Zulkharnay, Xiaoxing Ke, Meiyong Liao, Liwang Liu, Yujie Guo, Yejun Li, Horst-Guenter Rubahn, Victor V. Moshchalkov, Paul W. May
Summary: By investigating electrical transport phenomena, it is found that diamond nanorings (DNRs) transform into bosonic semiconductors upon the formation of Cooper pairs, exhibiting a sharp resistance increase and a giant negative magnetoresistance. In contrast, diamond half-loops (DHLs) undergo a metal-superconductor transition. This finding reveals the potential use of DNRs in manipulating Cooper pairs in superconducting quantum devices.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Ramiz Zulkharnay, Paul W. May
Summary: In situ observation reveals the large negative electron affinity (NEA) of scandium-terminated diamond, which shows high thermal stability up to 900 degrees C. The NEA values of -1.45 eV and -1.13 eV for diamond (100) and (111) surfaces, respectively, make them the highest measured NEA for a metal adsorbed onto bare diamond so far. This study provides insights into tuning the adsorbate-diamond interface and expands the material options for effective electron-emission applications.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Biochemical Research Methods
Joe Crossley-Lewis, Josh Dunn, Corneliu Buda, Glenn J. Sunley, Alin M. Elena, Ilian T. Todorov, Chin W. Yong, David R. Glowacki, Adrian J. Mulholland, Neil L. Allan
Summary: Interactive molecular dynamics simulation in virtual reality (iMD-VR) is a promising technique in molecular science, with applications in materials science and heterogeneous catalysis. This study demonstrates the use of iMD-VR in investigating lithium fast ion conduction mechanisms and exploring diffusion within zeolites.
JOURNAL OF MOLECULAR GRAPHICS & MODELLING
(2023)
Article
Chemistry, Physical
A. Archer, H. R. Foxhall, N. L. Allan, J. R. W. Shearer, D. S. D. Gunn, J. H. Harding, I. T. Todorov, K. P. Travis, J. A. Purton
Summary: This study reports molecular dynamics simulations of radiation damage cascades in different compounds, revealing the characteristics of increased volume and transition to amorphous structure in the titanium zirconate, while in the solid solution, increasing zirconium concentration can delay the onset of amorphization.
MOLECULAR SIMULATION
(2021)