Article
Physics, Multidisciplinary
Qing Lu, Chi Ding, Xiaomeng Wang, Tong Chen, Jian Sun
Summary: We performed first-principles calculations to analyze the electronic and superconducting properties of two hydrogenated graphene systems. The results show that the electronic properties depend on the hydrogenation positions and the distance between doped hydrogens can affect the movement of Dirac points. Superconductivity in the systems can be tuned by hole doping and tensile strains. Additionally, weak anharmonicity was found in the hydrogenated graphene systems.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Condensed Matter
Wei Wei, Shengqin Chen, Xiang Chen, Kai Zhou
Summary: We investigate the uniaxial strain dependence of electronic structure and thermoelectric properties of SnSe, and find that the band gap of SnSe can be tuned by uniaxial strain. Suitable uniaxial strains can significantly improve the Seebeck coefficient, electrical conductivity, and power factor of SnSe. Our findings provide an efficient strategy to modulate the thermoelectric properties of SnSe.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Optics
Wei Wei, Kai Zhou
Summary: In this study, the influence of uniaxial strain on the electronic and optical properties of SnSe was investigated using first-principles calculations and the Bethe-Salpeter equation (BSE) approach. The results showed that uniaxial strains have a significant impact on the density of states (DOS) in the valence and conduction bands by affecting the densities of Sn s/p-states and Se p-state. Suitable uniaxial strains can enhance the main peaks of the dielectric function's real (e1(?)) and imaginary (e2(?)) parts. The findings suggest that strain engineering can effectively modulate the optical properties of SnSe and has potential applications in solar energy conversion.
Article
Materials Science, Multidisciplinary
Hari Paudyal, Elena R. Margine
Summary: A new member of the TMD family, 2M-WS2, has been discovered to exhibit superconductivity with a critical temperature of 8.8 K, the highest among superconducting TMDs. Doping with Nb and Ta has been found to significantly enhance the superconducting properties of 2M-WS2, leading to a 50% increase in T-c, while doping with Mo and Se results in a monotonous decrease in T-c.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Physical
Rakshanda Dhawan, Vikrant Chaudhary, Tashi Nautiyal, Jeroen van den Brink, Hem C. Kandpal
Summary: Recent progress in the experimental and theoretical study of semiconducting CaAgP has led us to investigate its electrical and thermal transport properties using first-principles calculations. By using a hybrid functional, we find that CaAgP is a semiconducting material with a narrow band gap of approximately 0.15 eV, in agreement with experimental observations. Our results indicate that CaAgP is dynamically stable and has a gapped electronic band structure, making it potentially suitable for thermoelectric applications, particularly when p-doped.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Hyo-Sun Jin, Warren E. Pickett, Kwan-Woo Lee
Summary: First-principles investigations on the high-temperature superconducting system Ba2CuO3+delta, with a focus on oxygen ordering effects, reveal unique electronic and magnetic properties such as stretched Cu-plane oxygen distances and shortened Cu-apical oxygen separations. The system with strongly one-dimensional Cu-O-P chain structure shows 1D Fermi surfaces and antiferromagnetic chains. The energetically preferred structure for the superconducting phase involves a doubled bilayer structure with alternating Cu-O-P chains and Cu3O4 ladders.
Article
Chemistry, Physical
Shiquan Feng, Jiankang Liu, Jun Chen, Lei Su, Feng Guo, Cuiming Tang, Chaosheng Yuan, Xuerui Cheng
Summary: In this paper, van der Waals heterostructures composed of g-ZnO and Janus WSSe monlayers were designed, and their band alignments and band gaps were modulated by applying strains for potential applications in photoelectric devices and as catalysts for water splitting.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Biao Wang, Yurong He, Nikolay Rodionov, Jiaqi Zhu
Summary: This study compares and analyzes the effects of uniaxial and isotropic strains on the thermal conductivity of diamond using first-principles calculations and the phonon Boltzmann transport equation. The findings reveal that the bond length deformation index plays a significant role in the thermal conductivity of diamond under isotropic strain, while both the bond angle and bond length affect the thermal conductivity during uniaxial strain. This study provides essential insights into the strain-thermal conductivity relationships of diamond and other crystalline materials.
MATERIALS TODAY PHYSICS
(2023)
Article
Chemistry, Physical
Yutong Yao, Qihang Liang, Fawei Zheng, Menglei Li
Summary: In this study, first-principle calculations were used to investigate the structural, electronic, and superconducting properties of hydrogen-rich plutonium polyhydrides under high pressures. The results showed that these systems exhibited metallic behavior, with a low superconducting transition temperature. Additionally, it was found that the f electrons in plutonium had a detrimental effect on the superconductivity in these polyhydrides.
Article
Chemistry, Multidisciplinary
Dan Han, Xiaoheng Yang, Mu Du, Gongming Xin, Jingchao Zhang, Xinyu Wang, Lin Cheng
Summary: This study systematically investigates the thermoelectric properties of different WS2-WSe2 phononic crystals using first-principles calculations. It is found that the SL1 monolayer has the highest ZT value, at least twice as high as those of the WS2 and WSe2 monolayers; additionally, the PCH2 structure exhibits the best thermoelectric performance with significantly higher ZT values compared to the SL1 monolayer.
Article
Materials Science, Multidisciplinary
Haoran Chen, Xiao-Wei Zhang, Xin-Zheng Li, Junren Shi
Summary: This study presents a density-functional theory-based implementation of the stochastic path-integral approach for estimating the superconducting transition temperature of a liquid. The implementation, using the all-electron projector augmented-wave (PAW) method, includes generalizing the formalism to accommodate electron state pseudodescription and proposing a formula for constructing the overlap operator of the PAW method to eliminate errors due to pseudo basis set incompleteness. The implementation is applied to estimate Tc's of metallic hydrogen liquids, confirming the prediction that metallic hydrogen could form a superconducting liquid.
Article
Physics, Multidisciplinary
Fangzhou Zhao, Mark E. Turiansky, Audrius Alkauskas, Chris G. Van de Walle
Summary: Trap-assisted Auger-Meitner recombination is highlighted as a dominant nonradiative process in wide-band-gap materials, and a first-principles methodology is presented to determine the rates of this process in semiconductors or insulators due to defects or impurities.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Giovanni Marini, Antonio Sanna, Camilla Pellegrini, Christophe Bersier, Erio Tosatti, Gianni Profeta
Summary: Through first-principles study, a strong electron-phonon coupling linked to a structural phase transition and mitigated by Coulomb repulsion is found in Chevrel ternary superconductors. The study provides conclusive evidence explaining why Chevrel phases, despite their extreme electron-phonon coupling, have critical temperatures below 15K. Additionally, the predicted evolution of the superconducting critical temperature with external pressure agrees well with experimental data.
Article
Chemistry, Physical
Xuchang Tang, Zhaokai Luo, Yuanyuan Cui
Summary: The electronic and optical properties of RENiO3 under strain were studied using first-principles calculations. Tensile strength widens the band gap, while compressive strain increases light absorption. Machine learning algorithms revealed the key factors affecting band gaps and optical properties.
Article
Materials Science, Multidisciplinary
Hao-Jen You, Bo-Ying Su, Yi-Ting Chiang, Tse-Hsiao Li, Hsu-Shen Chu, Hsin Lin
Summary: The thermoelectric properties of n-type doped Sr2Si and Sr2Ge were investigated using first-principles density functional theory calculations and semi-classical Boltzmann transport theory. The multi-band feature in the conduction band of Sr2Ge leads to a higher Seebeck coefficient, resulting in a higher power factor. The phonon transport calculations predict ultra-low lattice thermal conductivity for both materials, with a maximum figure of merit of 1.44 for Sr2Ge at 900 K.
MATERIALS TODAY PHYSICS
(2023)
Article
Physics, Applied
A. Angrisani Armenio, A. Leveratto, G. de Marzi, A. Traverso, C. Bernini, G. Celentano, A. Malagoli
Summary: One unique feature of Bi-2212/Ag wires is the network of bridges formed by grains grown through the Ag matrix, which results in high critical current density but also increases AC losses and electrical coupling. This study investigates the behavior of these bridges under applied magnetic field and temperature, and their implications on electrical coupling, providing valuable insights for magnet design.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Nuclear Science & Technology
Lorenzo Giannini, Luigi Muzzi, Alfredo Portone, Gherardo Romanelli, Daniela P. Boso, Lorenzo Zoboli, Xabier Sarasola, Chiarasole Fiamozzi Zignani, Cesar Luongo, Valentina Corato, Jose Lorenzo Gomez, Christian Bachmann, Antonio della Corte
Summary: The European Roadmap to Fusion Electricity outlines the plan to complete the DEMO demonstration power plant within the next three decades, aiming for a net energy gain of Q=40. The design includes a 2 GW tokamak device with a 9 m plasma radius. The study explores the use of High Temperature Superconductors to improve the performance of the TFC winding pack and optimize the DTT central solenoid.
FUSION ENGINEERING AND DESIGN
(2023)
Article
Engineering, Electrical & Electronic
G. De Marzi, L. Muzzi, B. Bordini, A. Di Zenobio, F. Fabbri, C. Fiamozzi Zignani, A. Formichetti, R. Freda, L. Merli, G. Ramogida, S. Turtu, A. della Corte
Summary: This paper presents a practical parameterization of the critical surface of the 0.82-mm diameter Nb3Sn strands used for the Toroidal Field coils of the Italian Divertor Tokamak Test Facility. The critical current has been measured by means of a Walters Spring device as a function of uniaxial applied strain (+/- 0.5% intrinsic strain) at different field (up to 14 T) and in the temperature range comprised between 4.5 K and 10 K. The experimental results have been analyzed in the framework of the ITER-2008 parameterization and the Extrapolative Scaling Expression, by using a multi-step approach for the data fitting. The accuracy of the scaling laws provides an accurate parameterization of the critical surface in terms of field, temperature and strain, to be used for the characterization and production follow-up of the DTT qualification samples and coils.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Engineering, Electrical & Electronic
L. Muzzi, A. Augieri, G. Celentano, S. Chiarelli, A. della Corte, G. De Marzi, A. Di Zenobio, L. Giannini, M. Marchetti, A. Masi, G. Messina, A. Rufoloni, S. Turtu, A. Vannozzi, A. Bragagni, M. Seri, M. Arabi, A. Anemona, A. Formichetti
Summary: Technologies based on HTS are rapidly maturing, and several fusion projects are demonstrating the integration of HTS in coil systems. HTS has the potential to extend the operating space of fusion coils compared to LTS technologies, allowing for higher temperatures, magnetic field levels, and operating margins. The layout, feasibility, and performance demonstration of high-current conductors are crucial for HTS adoption.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Engineering, Electrical & Electronic
Antonio Macchiagodena, Marco Breschi, Deborah Buonafine, Gianluca De Marzi, Laura Savoldi
Summary: The ongoing design activities for the European post-ITER fusion demonstrator reactor (DEMO) have proposed options for high-temperature superconducting (HTS) magnets. This paper presents the development of tools for calculating magnetization losses in a twisted-stacked HTS cable, which is a promising configuration for HTS fusion conductors. The methodology allows for the treatment of twisted conductors by discretizing them into straight pieces.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Engineering, Electrical & Electronic
F. Giorgetti, G. De Marzi, L. Muzzi, A. Di Zenobio, P. Fanelli, L. Giannini, G. Ramogida, G. Tomassetti, S. Turtu, A. della Corte
Summary: The Divertor Tokamak Test facility (DTT) is a nuclear fusion device being constructed in the Research Centre of ENEA Frascati to address the power exhaust issue in future fusion power plants. This study evaluates the conceptual design and performance of the DTT superconducting magnet feeders using coupled electromagnetic and structural analyses. A preliminary structural assessment of the feeder clamps under self-field and maximum force per unit length conditions is presented, considering a 2D model with plane stress and thickness formulation. Bolt dimension, class, and distance between clamps are provided for both conditions.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Physics, Applied
He Ding, Gianluca De Marzi, Yuanwen Gao
Summary: Given the importance of large-scale engineering applications of Nb3Sn, researchers have been interested in its use and performance under specific operating conditions. This paper investigates the fracture behaviors in polycrystalline Nb3Sn and Nb3Sn filaments with composite structures using micromechanical finite element models. The study reveals that pre-existing cracks and martensitic phase transformation significantly affect the fracture properties in polycrystalline Nb3Sn. Additionally, detailed finite element models of different types of filaments are developed based on experimental observations for fracture analysis.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Correction
Computer Science, Information Systems
Daniele Placido, Gianluca De Marzi, Luigi Muzzi, Laura Savoldi
Article
Computer Science, Information Systems
Daniele Placido, Gianluca De Marzi, Luigi Muzzi, Laura Savoldi
Summary: The superconducting coils of the DTT facility are connected to the current leads through SC feeders made of commercial NbTi strands. These feeders operate in a magnetic field generated by the SC coil and plasma, reaching a maximum field strength of 4 T. The performance of the feeders is evaluated during a plasma pulse, considering different cabling configurations to withstand the nominal current at the peak field. The optimal design of the feeder cables is identified based on techno-economic analysis.
Article
Computer Science, Information Systems
Andrea Zappatore, Gianluca De Marzi, Davide Uglietti
Summary: This study investigates conductor design using high temperature superconducting (HTS) stacked tapes for fusion coils and estimates hysteresis losses using a numerical model. The results show that coupling losses are orders of magnitude lower than hysteresis losses, and the impact of hysteresis+coupling losses on the temperature margin of the coil is assessed. An alternative conductor concept is also analyzed.