Article
Chemistry, Physical
William Lafargue-Dit-Hauret, Mathieu Allix, Bruno Viana, Stephane Jobic, Camille Latouche
Summary: This study investigates the point defects in the well-known Y3Al5O12 (YAG) compound using computational methods. The results show that Y-Al antisites at Al octahedral position cannot be avoided regardless of the synthesis atmosphere, and V-O oxygen vacancies are easily formed under reducing atmospheres. Additionally, the transition level of Ce3+/Ce4+ charge gradually approaches the experimental value with a Hubbard correction of U-eff of 5 eV. Electron traps associated with the reduction of Cr3+ into Cr2+ species were also identified near the conduction band.
THEORETICAL CHEMISTRY ACCOUNTS
(2022)
Article
Nanoscience & Nanotechnology
M. Petrik, Yu N. Gornostyrev, P. A. Korzhavyi
Summary: The study systematically investigated the interactions of alloying elements and vacancies with coherent interfaces of the theta' phase in Al-based alloys, revealing that the presence of vacancies in the interfacial Cu layer plays a crucial role in solute-interface interactions. The solute-interface interaction energies were found to be weaker for elements with closed or empty d-electron shells compared to d-transition metals. The roles of alloying elements and interface structure in the stability of theta' phase precipitates were analyzed in terms of electronic structure and atomic size contributions to interatomic bonding.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Multidisciplinary
Denis Yagodkin, Kyrylo Greben, Alberto Eljarrat Ascunce, Sviatoslav Kovalchuk, Mahdi Ghorbani-Asl, Mitisha Jain, Silvan Kretschmer, Nikolai Severin, Juergen P. Rabe, Arkady Krasheninnikov, Christoph T. Koch, Kirill Bolotin
Summary: A new localized excitonic state is demonstrated in patterned monolayer 2D semiconductors. The state is distinguished by non-linear power dependence and can survive up to room temperature. It is shown to be of extrinsic origin, likely associated with charge transfer excitons from the organic substance deposited onto the 2D semiconductor.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Physics, Multidisciplinary
Kyung-Su Kim, Chaitanya Murthy, Akshat Pandey, Steven A. Kivelson
Summary: This study investigates the magnetism of two-dimensional Wigner crystals in two-dimensional electron gases, particularly in the strongly interacting regime. The results suggest that under certain conditions, a fully polarized ferromagnetic insulator can be formed.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Damla Yesilpinar, Martin Vondracek, Patrik Cermak, Harry Monig, Jaromir Kopecek, Ondrej Caha, Karel Carva, Cestmir Drasar, Jan Honolka
Summary: We investigated the effect of low concentrations of iron on the physical properties of SnS van der Waals crystals grown from the melt. Through scanning tunneling microscopy (STM) and photoemission spectroscopy, we studied Fe-induced defects and observed an electron doping effect in the band structure of the native p-type SnS semiconductor. Our results showed that Fe preferentially occupies donor-like interstitial Fe-int sites in close proximity to V-Sn defects along the high-symmetry c-axis of SnS, leading to a reduction of p-type carrier concentrations.
Article
Materials Science, Multidisciplinary
Cody A. Dennett, Zilong Hua, Eric Lang, Fei Wang, Bai Cui
Summary: High entropy carbides ceramics with randomly-distributed multiple principal cations exhibit high temperature stability, low thermal conductivity, and possible radiation tolerance. This study investigates the effects of extrinsically-generated structural defects on thermal transport and finds that nanoscale defects can effectively reduce thermal conductivity.
MATERIALS RESEARCH LETTERS
(2022)
Article
Chemistry, Physical
Lei Ao, Zhihua Xiong
Summary: Our study reveals that SD-59 exhibits high mobility in puckered arsenene but requires extremely low temperatures to observe, while DV-55557777 is identified as the ground state defect in arsenene, differing from phosphorene. The merging of SDs into DV is energetically favored and the indirect-to-direct transition in arsenene can be achieved through defect engineering.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Mark E. Turiansky, Chris G. Van de Walle
Summary: In this study, first-principles calculations are used to investigate V-B-C-B and V-B-Si-B complexes in cubic boron nitride as potential quantum defects. It is found that these complexes possess a triplet ground-state spin similar to the NV center in diamond, and their main optical transition occurs in the telecom O-band, making them attractive for quantum networking applications.
Article
Physics, Condensed Matter
Alina Kononov, Cheng-Wei Lee, Ethan P. Shapera, Andre Schleife
Summary: This study reevaluates native point defect geometries in alpha-Al2O3 and identifies new defect configurations that could have transformative impacts on our understanding of defect migration pathways in aluminum-oxide scales.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Physical
Shengjiong Yang, Shengshuo Xu, Jiayao Tong, Dahu Ding, Gen Wang, Rongzhi Chen, Pengkang Jin, Xiaochang C. Wang
Summary: The study uncovered the role of nitrogen dopant in carbon catalysts, where nitrogen is partially evaporated at high temperature to form topological intrinsic defects, promoting the activation of peroxymonosulfate and organic degradation through an electron-transfer mechanism. The findings suggest that surface-activated PMS complex is the main reactive oxidation species for organic degradation.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Materials Science, Multidisciplinary
Zhongzhong Zheng, Yuxing Bai, Yijie Ren, Huimin Chen, Li Wu, Yongfa Kong, Yi Zhang, Jingjun Xu
Summary: This study uncovers the mechanisms of photoluminescence and mechanoluminescence by controlling defects in the lattice. Oxygen vacancy defects play a crucial role in photoluminescence, while extrinsic cation substitution defects affect the mechanoluminescence of doped samples.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Multidisciplinary Sciences
Yong Zhu, Lei Tao, Xiya Chen, Yinhang Ma, Shoucong Ning, Jiadong Zhou, Xiaoxu Zhao, Michel Bosman, Zheng Liu, Shixuan Du, Sokrates T. Pantelides, Wu Zhou
Summary: Point defects in anisotropic ReSe2 offer potential for defect engineering, with vacancies, isoelectronic substitutions, and antisite defects being investigated through experimental and computational methods. The results provide atomic-scale insight into defect engineering of ReSe2, paving the way for tuning its electronic structure.
Article
Physics, Fluids & Plasmas
K. S. Krishnamurthy, D. S. Shankar Rao, Madhu B. Kanakala, Channabasaveshwar Yelamaggad
Summary: This study investigates the effect of low-frequency electric fields on elastic dipoles in twist-bend nematic droplets, finding that the dipoles shift towards the negative electrode in static fields and oscillate in AC fields. Moreover, the translational velocity of the dipoles increases linearly with frequency and the diameter of the droplets, showing a slightly nonlinear variation with increasing applied voltage at lower frequencies.
Article
Chemistry, Physical
Rina Ibragimova, Patrick Rinke, Hannu-Pekka Komsa
Summary: This study investigates the formation energies of metal, carbon, and nitrogen vacancies in MXene materials using first-principles calculations. The results show significant differences in the formation energies of metal vacancies under different surface functionalizations and environments. Carbon and nitrogen vacancies are found to be more prevalent in oxygen-functionalized surfaces. The study also highlights the influence of pH value and electrode potential on vacancy formation.
CHEMISTRY OF MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Marie Krecmarova, Rodolfo Canet-Albiach, Hamid Pashaei-Adl, Setatira Gorji, Guillermo Munoz-Matutano, Milos Nesladek, Juan P. Martinez-Pastor, Juan F. Sanchez-Royo
Summary: Color defects were successfully generated in hBN nanosheets dispersed on different substrates through thermal treatment processes, with subsequent ozone treatments improving the optical emission properties. Defects deposited on dielectric substrates exhibited bright and stable light emission, with a wide range of zero-phonon line peak energies. Additionally, a substrate dependence of the optical performance of the color defects was observed, with gold substrates leading to a reduction in energy range due to quenching effects.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Amit Samanta, Joel B. Varley, Vincenzo Lordi
Summary: Using hybrid functional-based density functional theory calculations, the study analyzed the structure and kinetics of defects in hydrogen-doped In2O3 films synthesized through different routes. The results indicate that H+ is the dominant defect species and water molecules split into H+ and OH-. The defects do not cluster but remain spatially distributed throughout the films.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Sandra Hultmark, Alex Cravcenco, Khushbu Kushwaha, Suman Mallick, Paul Erhart, Karl Borjesson, Christian Mueller
Summary: The study demonstrates that mixing organic molecules can reduce fragility, with octonary perylene mixtures showing a remarkably low fragility value. This opens up a new avenue for designing ultrastrong organic glass formers.
Article
Chemistry, Inorganic & Nuclear
Yifei Zhang, Joakim Brorsson, Takashi Kamiyama, Takashi Saito, Paul Erhart, Anders E. C. Palmqvist
Summary: This study investigates the chemical ordering in quaternary clathrates Ba8AlxGa16-xGe30, revealing differences in site occupancy factors of trivalent elements and atomic displacement patterns of Ba atoms based on synthesis methods. The research demonstrates key relationships between chemical ordering and structural properties, providing new insights for designing and optimizing thermoelectric materials.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Chang-Eun Kim, Jiwoo Lee, Aron Walsh, Vincenzo Lordi, David F. Bahr
Summary: This study used density functional theory to calculate the energy and electronic structure of graphene models with different curvatures and hydrogen adsorption sites. The study found that the orientation of ripples affects the bandgap of graphene, while the adsorption energy of hydrogen depends on the curvature. Adsorbed hydrogen alters the curvature, resulting in weakened adsorption on neighboring sites, explaining the experimentally observed dynamic equilibrium stoichiometry of hydrogenated graphene.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Joakim Brorsson, Anders E. C. Palmqvist, Paul Erhart
Summary: The study used a combination of theoretical and computational simulation methods to explore compositions with high power factors in clathrates, considering cost factors. The results showed that cost-effective performance can be achieved by reducing the number of Al and Ga atoms, while using extrinsic dopants.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Multidisciplinary Sciences
Joakim Brorsson, Arsalan Hashemi, Zheyong Fan, Erik Fransson, Fredrik Eriksson, Tapio Ala-Nissila, Arkady Krasheninnikov, Hannu-Pekka Komsa, Paul Erhart
Summary: High-order force constant expansions, combined with GPU-accelerated molecular dynamics simulations, provide an accurate, transferable, and efficient approach for sampling the dynamical properties of materials.
ADVANCED THEORY AND SIMULATIONS
(2022)
Article
Nanoscience & Nanotechnology
Mikael Kuisma, Benjamin Rousseaux, Krzysztof M. Czajkowski, Tuomas P. Rossi, Timur Shegai, Paul Erhart, Tomasz J. Antosiewicz
Summary: Ultrastrong coupling refers to a unique mode of interaction between light and matter, where the coupling strength is comparable to the resonance energy of the cavity or emitter. Traditional approximations to quantum optical Hamiltonians fail in the ultrastrong coupling regime, as the ground state of the coupled system obtains photonic characteristics, resulting in changes in ground-state energy. Using time-dependent density functional theory calculations, we demonstrate that a single organic molecule can achieve ultrastrong coupling with a plasmonic dimer comprising of a few hundred atoms. The ultrastrong coupling leads to significant modifications in ground-state energy, accounting for a considerable portion of the total interaction energy.
Article
Nanoscience & Nanotechnology
Pernilla Ekborg-Tanner, J. Magnus Rahm, Victor Rosendal, Maria Bancerek, Tuomas P. Rossi, Tomasz J. Antosiewicz, Paul Erhart
Summary: This study utilized a multiscale modeling approach to determine optimal conditions for optical hydrogen sensing using the Pd-Au-H system, and observed the pattern of optical sensitivity changing with hydrogen concentration at the single nanoparticle level. While alloy composition has limited impact, it strongly affects hydrogen uptake and thermodynamic sensitivity.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Physical
Christopher Linderaelv, J. Magnus Rahm, Paul Erhart
Summary: Alloying can tune the properties of transition metal dichalcogenide (TMD) monolayers. This study investigates the phase diagrams and mixing behavior of 72 TMD monolayer alloys through first-principles calculations and alloy cluster expansions. It is found that ordered phases are generally absent at room temperature, but certain alloys exhibit a stable Janus phase. Additionally, the band edge positions of some alloys can be continuously tuned within the range set by the boundary phases.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jakub Fojt, Tuomas P. Rossi, Mikael Kuisma, Paul Erhart
Summary: This study models the generation of hot carriers across the interface between plasmonic nanoparticles and a CO molecule, finding that the hot electron transfer probability depends on the distance, energetic alignment, and excitation frequency, while hot hole transfer is limited to shorter distances. The hybridization of molecular orbitals is the key predictor for hot carrier transfer.
Article
Nanoscience & Nanotechnology
Aedan Gardill, Ishita Kemeny, Yanfei Li, Maryam Zahedian, Matthew C. Cambria, Xiyu Xu, Vincenzo Lordi, Adam Gali, Jeronimo R. . Maze, Jennifer T. Choy, Shimon Kolkowitz
Summary: Super-resolution Airy disk microscopy, a novel technique presented in this study, allows nanoscale microscopy in a standard confocal microscope without specialized optics. The technique, combined with ground state depletion, successfully images and controls NV centers in diamond below the diffraction limit, achieving more than 14-fold improvement in resolution compared to the conventional limit.
Editorial Material
Chemistry, Physical
Paul Erhart, J. Magnus Rahm
Summary: This apparent mathematical quirk utilizes symmetry to resolve the issue of determining the equilibrium shape of asymmetrical terminations in two-dimensional materials crystals.
Article
Physics, Applied
Amit Samanta, Stephan Friedrich, Kyle G. Leach, Vincenzo Lordi
Summary: Several current searches for physics beyond the standard model are focused on electron-capture decay of radionuclides implanted in cryogenic high-resolution sensors. Understanding the effects of the host material on the electron energy levels is necessary for accurate measurements. Using density-functional theory, the electronic structure of lithium in different atomic environments of a polycrystalline tantalum absorber film was modeled. The results show variation in binding energies and broadening of energy levels due to lattice sites, grain boundaries, and impurities, contributing to sensor peak broadening but not fully explaining it.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Multidisciplinary
M. C. Cambria, A. Norambuena, H. T. Dinani, G. Thiering, A. Gardill, I. Kemeny, Y. Li, V. Lordi, A. Gali, J. R. Maze, S. Kolkowitz
Summary: In this study, measurements of spin-lattice relaxation of the nitrogen-vacancy (NV) center were conducted as a function of temperature from 9 to 474 K. It was found that the temperature dependence of the relaxation rates can be explained by a theory of Raman scattering due to second-order spin-phonon interactions. The study also suggests that the high-temperature behavior of NV spin-lattice relaxation is dominated by interactions with two groups of quasi-localized phonons.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Martin Rahm, Paul Erhart, Roberto Cammi
Summary: Compression reveals the connection between van-der-Waals radii and electronegativity, and their relationships to the driving forces behind chemical and physical transformations.