Article
Chemistry, Physical
Wenhan Zhou, Shengli Zhang, Jiang Cao, Zhenhua Wu, Yangyang Wang, Yunwei Zhang, Zhong Yan, Hengze Qu, Haibo Zeng
Summary: A device architecture strategy is proposed to modulate tunneling probability and achieve high on-state current in 5 nm boron phosphide TFETs. Through abundant simulation studies, it is found that BP TFETs with spacer and pocket structures can achieve a large on-state current.
Article
Physics, Fluids & Plasmas
N. M. Gill, C. J. Fontes, C. E. Starrett
Summary: The study focused on the opacity of iron, chromium, and nickel plasmas under experimental conditions at Sandia National Laboratories. Calculations showed that channel mixing effects slightly increased opacity in iron plasmas, but did not affect chromium and nickel plasmas. This indicates that channel mixing effects do not explain the opacity trends observed in the experiments.
Article
Materials Science, Multidisciplinary
A. Aadhityan, Preferencial C. Kala, John D. Thiruvadigal
Summary: Understanding spin-dependent electron transport through single molecular junction is essential for constructing efficient molecular spintronic devices. Utilizing Density Functional Theory and Non Equilibrium Green's Function helps to investigate the electron transport properties of different molecular positional isomers, with 2,5-dibromobenzene-1,3-dithiol showing a higher magnetoresistance effect and potential for spintronic applications.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Sooheon Cho, Byung Joo Jeong, Kyung Hwan Choi, Bom Lee, Jiho Jeon, Sang Hoon Lee, Bum Jun Kim, Jae-Hyun Lee, Hyung-Suk Oh, Hak Ki Yu, Jae-Young Choi
Summary: A quasi-one-dimensional van der Waals metallic nanowire Nb2PdS6 was synthesized and its electrical characteristics were analyzed. The study found that Nb2PdS6 exhibited high crystallinity and a high breakdown current density. Moreover, the breakdown mechanism of the nanowires was attributed to Joule heating and was well described by a 1D thermal dissipating model.
Article
Astronomy & Astrophysics
C. J. A. P. Martins, Patrick Peter, I. Yu Rybak, E. P. S. Shellard
Summary: This analytic model extends the VOS model to describe the evolution of superconducting cosmic string networks, and derives equations to describe this evolution. It provides new opportunities for investigating observational signatures under more general equations of state.
Article
Physics, Multidisciplinary
Xiao Dong, Yuan Li, Tianxing Wang, Yipeng An, Yongyong Wang
Summary: The critical conditions of the insulator-to-metal transition in two types of Si-based intermediate-band materials were studied using molecular dynamics simulations and Landauer transmission calculations. It was found that the I-M transition of the substitutional configuration of S occurred when the filled intermediate band expanded and merged with the conduction band, in line with the Mott transition theory. On the other hand, for the substitutional configuration of N, which can be regarded as a standard intermediate-band material, the I-M transition occurred when the partially-filled intermediate band expanded and the carrier localization in the band weakened. The metallic state of the intermediate-band material exhibited some semiconductor properties at low temperature.
NEW JOURNAL OF PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Tetsuro Habe, Koichi Nakamura
Summary: The research reveals the presence of excitons in the monolayer crystal and evaluates its optical property using numerical methods. Additionally, it confirms the consistency of the optical property of the bulk crystal with previous experimental results, independent of the number of layers.
Article
Nanoscience & Nanotechnology
Mohamed A. Abdelati, Mohamed M. Fadlallah, Yosr E. E-D Gamal, Ahmed A. Maarouf
Summary: This study investigated the structural stabilities and optical properties of graphene quantum dots (GQDs) and holey GQDs with different sizes, edge terminations, and pore passivations using density functional theory (DFT) and time dependent DFT. Results showed that the optical spectra of GQDs primarily depend on their size, while pore passivation has the biggest effect on the absorption spectra of holey GQDs. These findings can be applied in the development of promising materials for various applications, such as biological sensors and optoelectronic devices.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Chemistry, Physical
Jiawei Zhan, Marco Govoni, Giulia Galli
Summary: Electronic structure calculations based on DFT have successfully predicted ground-state properties of molecules and materials. However, the currently used exchange and correlation functionals are often inaccurate for describing the electronic properties of heterogeneous solids. Here, we present a dielectric-dependent range-separated hybrid functional, SE-RSH, which accurately predicts the electronic structure of various nonmetallic interfaces, solids, and nanoparticles.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Physics, Multidisciplinary
Ni-Ping Shi, Shao-Xian Wang, Fei Tang, Zi-Qun Wang, Hui Huang, Guang-Ping Zhang
Summary: In this study, the spin transport properties of molecular devices consisting of transition metal-dibenzo-tetraaza[14]annulene complex (TM-DBTAA, TM=Co, Cu, Ni) connected to carbon nanotube electrodes were investigated using first-principles method. It was found that Co-DBTAA acts as a spin filter with a spin filtering efficiency close to 100%. O2 adsorption on the TM atom results in a change of spin polarization for Co-DBTAA, while for Ni-DBTAA, it induces a spin-up polarized current with a high spin filtering efficiency. This work provides insights for the future design of molecular spin filters and gas sensors.
Article
Engineering, Electrical & Electronic
Aijaz H. Lone, Shivangi Shringi, Kishan Mishra, Srikant Srinivasan
Summary: The study focused on the key metrics of a magnetic tunnel junction, including tunnel magnetoresistance (TMR), thermal stability, and critical switching current. Quantum transport and magnetization dynamics simulations were conducted to understand the effects of down-scaling the transverse dimensions of the MTJ. The study revealed important insights into the performance of MTJs as their dimensions decrease.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Physics, Multidisciplinary
Yi Guo, Peng Zhao, Gang Chen
Summary: The study examines the thermally-driven spin-dependent transport properties of a molecular junction using density functional theory and nonequilibrium Green function methodology. It demonstrates that magnetic field and light can regulate the currents effectively, leading to spin-filtering and thermal switching effects. Based on these properties, basic thermal spin molecular gates were designed.
Correction
Chemistry, Physical
Daniel R. Nascimento, Niranjan Govind
Summary: In this study, a computational method based on linear-response time-dependent density functional theory is developed for the calculation of XANES, VtC-XES, and RIXS, which is of significant importance for theoretical and experimental research in related fields.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Ansgar Pausch, Christof Holzer
Summary: The letter outlines the steps and derivations necessary to apply density functional approximations that depend on the current and kinetic energy density within linear-response methods. It also discusses the necessary exchange-correlation kernel and its implications for systems in strong external magnetic fields and with strong spin-orbit coupling. An application to calculating excited states of small molecules in strong external magnetic fields using linear-response time-dependent current density functional theory is presented as well.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Praful S. Patil, Nagaiyan Sekar
Summary: This study theoretically investigates the nonlinear optical properties of natural hydroxyanthraquinones using the DFT method, and the results indicate that these compounds exhibit appreciable NLO properties. The computational results are consistent with the reported experimental results.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2024)
Article
Chemistry, Physical
Xiaoyan Wu, Shizheng Wen, Huajing Song, Thomas Frauenheim, Sergei Tretiak, ChiYung Yam, Yu Zhang
Summary: This work presents an efficient nonadiabatic molecular dynamics simulation method based on TDDFTB theory, which accurately describes photophysical and photochemical phenomena and provides a theoretical simulation tool for predicting the properties of complex materials.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Christian F. A. Negre, Alejandro Lopez-Bezanilla, Yu Zhang, Prosper D. Akrobotu, Susan M. Mniszewski, Sergei Tretiak, Pavel A. Dub
Summary: Density matrix electronic structure theory is widely used in quantum chemistry to reduce computational cost. In this study, a method to compute the density matrix using a quadratic unconstrained binary optimization (QUBO) solver is proposed and explored. The algorithm's parameters, precision, and efficiency are investigated. The results show that the direct construction of the density matrix using a QUBO formulation is feasible but has room for improvement in terms of efficiency and precision. Alternative methods that could lead to a more efficient QUBO-based density matrix construction are suggested.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Carlos Mora Perez, Dibyajyoti Ghosh, Oleg Prezhdo, Wanyi Nie, Sergei Tretiak, Amanda Neukirch
Summary: This study investigates the impact of defects on the ground state electronic structure of two-dimensional RP halide perovskites. The research reveals that neutral-type point defects have limited influence on the electronic structure, while donor/acceptor defects introduce deep midgap states that can harm the material's electronic performance. Avoiding halide vacancies and interstitial defects is crucial to maintain positive intrinsic properties and improve device performance in 2D halide perovskite-based applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Shahriar N. Khan, Braden M. Weight, Brendan J. Gifford, Sergei Tretiak, Alan Bishop
Summary: The optoelectronic properties of functionalized graphene quantum dots were studied by simulating different shapes and types of functionalization. The results showed that the functionalization position and edge shape played important roles in the optical properties. The isomers with CH2 in the intermediate positions showed higher electronic transition energies and exciton delocalization. Complete passivation of rhombic GQDs resulted in the largest structural deformation and strongest red-shift. The substituents F, CH3, Cl, and Br caused a steady red-shift in the absorption energy, suggesting the dominance of steric effects.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Luo Yan, Jiaojiao Zhu, Bao-Tian Wang, Junjie He, Hai-Zhi Song, Weibin Chu, Sergei Tretiak, Liujiang Zhou
Summary: The study reports the discovery of two-dimensional transition metal oxide materials beyond the MXene family, which exhibit superconducting, semiconducting, and light-harvesting properties. This expands the understanding of emerging phenomena in this field and provides a new platform for optoelectronic and photovoltaic applications.
Article
Multidisciplinary Sciences
Yu Zheng, Yulun Han, Braden M. Weight, Zhiwei Lin, Brendan J. Gifford, Ming Zheng, Dmitri Kilin, Svetlana Kilina, Stephen K. Doorn, Han Htoon, Sergei Tretiak
Summary: By controlling the morphology of the emitting sites, spin-selective photochemistry diversifies the tunability of carbon nanotube emission.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Hsinhan Tsai, Dibyajyoti Ghosh, Eli Kinigstein, Bogdan Dryzhakov, Honora Driscoll, Magdalena Owczarek, Bin Hu, Xiaoyi Zhang, Sergei Tretiak, Wanyi Nie
Summary: The dynamic structure changes in metal halide perovskite lattice upon photoexcitation and its impact on carrier transport properties in Ruddlesden-Popper phase perovskite thin films are reported in this study. Time-resolved X-ray scattering technique reveals rapid lattice expansion and slow relaxation over 100 ns after photoexcitation. The expansion is attributed to lattice thermal fluctuations caused by photon energy deposition. High laser powers induce strong local structural disorder, increasing the charge dissociation activation energy and leading to localized transport.
Correction
Chemistry, Multidisciplinary
Nikita Fedik, Roman Zubatyuk, Maksim Kulichenko, Nicholas Lubbers, Justin S. Smith, Benjamin Nebgen, Richard Messerly, Ying Wai Li, Alexander I. Boldyrev, Kipton Barros, Olexandr Isayev, Sergei Tretiak
NATURE REVIEWS CHEMISTRY
(2022)
Article
Mechanics
M. Serrano, K. Larkin, M. Ghommem, S. Tretiak, A. Abdelkefi
Summary: A multi-purpose energy harvesting microgyroscope system based on piezoelectric materials is proposed for small devices in remote areas. Numerical analysis shows that a system with a non-symmetric beam design is suitable for broadband energy harvesting. The nonlinear softening effects create a broadband frequency response with high voltage output, but careful selection of DC and AC voltages is necessary to avoid dynamic pull-in.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Mechanics
M. Serrano, K. Larkin, S. Tretiak, A. Abdelkefi
Summary: Most microelectromechanical systems (MEMS) are made from brittle materials that are prone to cracking. Understanding the potential influences cracks in MEMS is necessary for the longevity of these systems. This study developed an electromechanical model to capture the impacts of cracks on the performance of a damaged energy harvesting microgyroscope, and numerical methods were used to approximate the damage associated with distributed crack networks. The study revealed that cracks can significantly affect the static and dynamic behaviors of the microgyroscope energy harvester.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Chemistry, Physical
Hassiel Negrin-Yuvero, Victor M. Freixas, Dianelys Ondarse-Alvarez, Ana E. Ledesma, Sergei Tretiak, Sebastian Fernandez-Alberti
Summary: The photoexcitation, energy relaxation, and redistribution of a recently synthesized zigzag carbon nanobelt were studied using molecular dynamics simulations. The transition dipole moments and electronic transition density were found to gradually change during the internal conversion process. The electronic relaxation involved long-lived states with large energy gaps and changes in symmetry. These results provide insights into the excited-state properties of the zigzag nanobelt and can inspire the design of tailored nanobelts for specific nanoelectronic and photonic applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Chintam Hanmandlu, Rohan Paste, Hsinhan Tsai, Shyam Narayan Singh Yadav, Kuan-Wen Lai, Yen-Yu Wang, Chandra Shekar Gantepogu, Chen-Hung Hou, Jing-Jong Shyue, Yu-Jung Lu, Tushar Sanjay Jadhav, Jian-Ming Liao, Hsien-Hsin Chou, Hui Qi Wong, Chao-Sung Lai, Dibyajyoti Ghosh, Sergei Tretiak, Ta-Jen Yen, Hung-Ju Yen, Chih-Wei Chu
Summary: This study used a holistic interface strategy to enhance the efficiency and stability of perovskite solar cells by decreasing the number of interfacial defect states. The researchers utilized three-dimensional triphenylamine-based nanographene precursors to form a bridge between the perovskite film and the hole transport layer, resulting in improved performance characteristics.
Article
Chemistry, Physical
Hassiel Negrin-Yuvero, Victor M. Freixas, Dianelys Ondarse-Alvarez, Ana E. Ledesma, Sergei Tretiak, Sebastian Fernandez-Alberti
Summary: Progress in the synthesis of new carbon nanorings and nanobelts broadens the library of materials with unique structural and optical properties that can be attractive for further potential applications in host-guest chemistry, nanoelectronics, and photonics. In this study, we investigate the photoexcitation and subsequent energy relaxation and redistribution of a recently synthesized zigzag carbon nanobelt using nonadiabatic excited state molecular dynamics simulations. Our results reveal the excited-state dynamical properties of the zigzag-type nanobelt that differentiate this molecule from other nanobelts, providing insights for further designs tailored for specific nanoelectronic and photonic applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Multidisciplinary Sciences
Guoqing Zhou, Nicholas Lubbers, Kipton Barros, Sergei Tretiak, Benjamin Nebgen
Summary: Conventional machine learning models in computational chemistry predict molecular properties using quantum chemistry, but their accuracy degrades on larger or newer chemical systems. Incorporating quantum chemistry frameworks into machine learning models improves accuracy. This study demonstrates accurate prediction of various molecular properties on larger chemical systems by using machine-learned dynamic values in semiempirical quantum mechanics.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Chemistry, Physical
Laura Alfonso Hernandez, Victor M. Freixas, Beatriz Rodriguez-Hernandez, Sergei Tretiak, Sebastian Fernandez-Alberti, Nicolas Oldani
Summary: The effect of introducing a satellite tetraphenyl substitution on the structural and dynamical properties of cycloparaphenylene is studied. The results show that the substitution accelerates the electronic relaxation and induces efficient inter-band energy transfer and exciton self-trapping.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
