Article
Materials Science, Ceramics
Komal K. Jani, Pooja Y. Raval, Nimish H. Vasoya, Monika Nehra, Mamraj Singh, Narendra Jakhar, Sandeep Kumar, Kunal B. Modi, Dong-Kwon Lim, Rishi Kumar Singhal
Summary: X-ray photoelectron spectroscopy (XPS) was used to investigate the electronic structure of Zn0.3Mn0.7+xSixFe2-2xO4 ferrite series. The results revealed the presence of Si ions in the +4 valence state. Silicon-oxygen (Si-O) and suboxide SiOx were found to be present in the system, with an increase in Si-O content and a decrease in SiOx content upon Mn-Si substitution. The Fe2p XPS spectra indicated the co-occurrence of ferrous and ferric ions in the system, with ferrous ions occupying octahedral sites and ferric ions dwelling on both octahedral and tetrahedral sites. The O1s spectra showed an increase in oxygen defects with increasing Mn-Si substitution. The Mn2p XPS data showed an overall increasing trend in the Mn+2 states and an increment in the Mn+4/Mn+3 ratio with increasing Mn-Si substitution.
CERAMICS INTERNATIONAL
(2022)
Review
Chemistry, Multidisciplinary
Hebatallah Ali, Bernd Winter, Robert Seidel
Summary: The liquid-microjet technique combined with soft X-ray photoelectron spectroscopy is a powerful tool for investigating the electronic structure of liquid water and nonaqueous solvents and solutes, including nanoparticle suspensions. This Account focuses on NPs dispersed in water, exploring the interaction between water molecules and the surface of transition-metal oxide NPs.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Alexander B. Shick, Shin-ichi Fujimori, Warren E. Pickett
Summary: Correlated band theory based on density functional theory with exact diagonalization was applied to UTe2, revealing its physical properties at different U values, including a transition to a semimetallic state at U = 3 eV. Predictions were made for the Kondo temperature of UTe2 and the electric field gradient difference between uranium and tellurium sites, consistent with experimental observations.
Article
Chemistry, Multidisciplinary
Cesar D. D. Mendoza, F. L. Freire Jr
Summary: We investigated the interfacial electronic structure of single-layer graphene on a germanium substrate using UPS and XPS. The graphene was directly synthesized on (110) undoped Ge substrate via CVD. The study identified the main graphitic properties and showed that the Ge substrate affected the electronic structure of the graphene due to electronic coupling. The study also provided important information on the Schottky contact's nature and energy level alignments for potential integration of single-layer graphene on a Ge substrate with CMOS technology.
Article
Chemistry, Physical
Vadim Yu. Samardak, Alexander A. Komissarov, Alexander A. Dotsenko, Vladimir V. Korochentsev, Ivan S. Osmushko, Anton A. Belov, Pavel S. Mushtuk, Valerii A. Antonov, Ghader Ahmadpour, Farzad Nasirpouri, Alexander S. Samardak, Alexey V. Ognev
Summary: The Neodymium-iron-boron magnetic oxide powders synthesized by sol-gel Pechini method were investigated using X-ray photoelectron spectroscopy (XPS) and quantum chemical modeling. The powder structure was examined by X-ray diffraction (XRD) and modeled using density functional theory (DFT) approximation. The electronic structures of the core and valent regions were determined experimentally by X-ray photoelectron spectroscopy and modeled using quantum chemical methods. This study offers valuable insights into the electronic structure and chemical bonding of NdFeCoB oxide particles with the substitution of Fe by Co atoms.
Article
Chemistry, Physical
R. Garza-Hernandez, H. J. Edwards, J. T. Gibbon, M. R. Alfaro-Cruz, V. R. Dhanak, F. S. Aguirre-Tostado
Summary: Cu2SnS3 thin films were synthesized using two different routes in an aprotic media. Controlling the sulfurization temperature allowed for the presence of diverse crystalline structures of Cu2SnS3. XPS measurements confirmed the presence of Sn4+ and Cu+ species, while bandgap values varied with different crystal phases. The films showed photoconductive properties, making them a potential option for solar applications.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Sirak M. Mekonen, Chang -Jong Kang, Dipanjan Chaudhuri, David Barbalas, Sheng Ran, Gabriel Kotliar, Nicholas P. Butch, N. P. Armitage
Summary: This paper investigates the normal state electronic structure of the newly discovered superconductor UTe2. The MIR peak observed in the optical conductivity is attributed to interband transitions involving a narrow U 5 f feature. Experimental data shows the presence of low-energy Kondo resonance above the onset of superconductivity, implicating heavy electrons in the formation of the superconducting state.
Article
Materials Science, Ceramics
Komal K. Jani, Divyesh V. Barad, Pooja Y. Raval, Monika Nehra, Nimish H. Vasoya, Narendra Jakhar, Kunal B. Modi, Sandeep Kumar, Dong-Kwon Lim, Rishi Kumar Singhal
Summary: The electronic structure study of the quadruple perovskite series reveals the valence states of Ti, Cu, and Ca ions, as well as the possible presence of surface atoms and hybridization phenomena. Additionally, oxygen vacancies may partially contribute to the shift in the O1s spectra peaks.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Jia Liu, Shitan Wang, Baopeng Yang, Haipeng Xie, Han Huang, Dongmei Niu, Yongli Gao
Summary: The protective effect of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) passivation layer on the environmental stability of black phosphorus (BP) was studied. It was found that NTCDA can improve the environmental stability of BP and slow down the surface oxidation and degradation.
RESULTS IN PHYSICS
(2022)
Article
Chemistry, Physical
Fedor Y. Naumkin
Summary: The study of composite nanosystems focused on the molecular interfaces between materials like carbon and aluminum reveals the possibility of symmetric aluminum clusters with the insertion of suitable carbon skeletons. Brighter IR spectra and high focus on core-shell isomers are found, indicating potential applications in molecular electronics. Structural details of the system are reflected in the IR spectra, facilitating experimental analysis and detection of species formation and transformation.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Multidisciplinary
A. Merentsov, A. S. Shkvarin, M. S. Postnikov, L. Gregoratti, M. Amati, P. Zeller, P. Moras, A. N. Titov
Summary: The morphology of heterogeneous CrxTi1-xSe2 and CrxTi1-xS2 single crystals was studied using X-ray scanning photoemission microscopy (SPEM) and angular resolved photoemission spectroscopy (ARPES). The formation of structural fragments inside CrxTi1-xSe2 single crystals was confirmed to depend on the chalcogen (S, Se) forming the crystal lattice.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Biochemistry & Molecular Biology
Naipisai Wumaierjiang, Bumaliya Abulimiti, Fengzi Ling, Mei Xiang, Xulan Deng, Jie Wei, Bing Zhang
Summary: This study investigates the excited state dynamics of 2-methylpyrazine and observes its decay pathways via intersystem crossing and internal conversion.
Article
Multidisciplinary Sciences
Chunruo Duan, R. E. Baumbach, Andrey Podlesnyak, Yuhang Deng, Camilla Moir, Alexander J. Breindel, M. Brian Maple, E. M. Nica, Qimiao Si, Pengcheng Dai
Summary: Superconductivity arises from electron Cooper pairs that can move without resistance below a certain temperature. In some materials, such as UTe2, spin-triplet pairing is possible, which is important for quantum computation. The observation of sharp magnetic excitation in UTe2 suggests a possible coupling between superconductivity and antiferromagnetic spin fluctuations.
Article
Chemistry, Physical
Weronika O. Razmus, Kyle Acheson, Philip Bucksbaum, Martin Centurion, Elio Champenois, Ian Gabalski, Matthias C. Hoffman, Andrew Howard, Ming-Fu Lin, Yusong Liu, Pedro Nunes, Sajib Saha, Xiaozhe Shen, Matthew Ware, Emily M. Warne, Thomas Weinacht, Kyle Wilkin, Jie Yang, Thomas J. A. Wolf, Adam Kirrander, Russell S. Minns, Ruaridh Forbes
Summary: The structural dynamics of photoexcited gas-phase carbon disulfide molecules were investigated using ultrafast electron diffraction, revealing the processes of optical excitation and molecular dissociation, as well as the energy level transitions and fragment generation between different electronic systems.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Chao-Jiang Zhang, Filiberto Ortiz-Chi, Xi-Ling Xu, Hong-Guang Xu, Gabriel Merino, Wei-Jun Zheng
Summary: The study explored the structures of C2Al4-/0 and C(2)Al(5)(-/0) using different techniques. It was found that C2Al4- has a boat-like structure consisting of a C-2 unit surrounded by four aluminum atoms. In contrast, the neutral C2Al4 species has a planar structure with two ptC units. The most stable isomer of C2Al5- adopts a D-3h symmetry with the C(2) unit interacting with five aluminum atoms.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Physics, Multidisciplinary
Hiroki Fujibayashi, Genki Nakamine, Katsuki Kinjo, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki
Summary: This study investigates the spin susceptibility in U-based superconductor UTe2 in the superconducting state. The results indicate that the spin susceptibility remains nearly unchanged below the superconducting transition temperature. Furthermore, the study shows that UTe2 is a spin-triplet superconductor with spin degrees of freedom.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
Takatsugu Koizumi, Fuminori Honda, Yoshiki J. Sato, Dexin Li, Dai Aoki, Yoshinori Haga, Jun Gouchi, Shoko Nagasaki, Yoshiya Uwatoko, Yoshio Kaneko
Summary: The research team successfully grew single crystals of a new ternary Eu-divalent compound, EuPt3Al5, and observed its antiferromagnetic ordering. Pressure has a significant influence on the antiferromagnetic ordering of EuPt3Al5, and it suddenly disappears above 9 GPa, accompanied by a dramatic change in the Eu electronic states.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
Dai Aoki, Hironori Sakai, Petr Opletal, Yoshifumi Tokiwa, Jun Ishizuka, Youichi Yanase, Hisatomo Harima, Ai Nakamura, Dexin Li, Yoshiya Homma, Yusei Shimizu, Georg Knebel, Jacques Flouquet, Yoshinori Haga
Summary: This study reports the first observation of the de Haas-van Alphen (dHvA) effect in the novel spin-triplet superconductor UTe2. The researchers found that UTe2 has two types of cylindrical Fermi surfaces with strong corrugation, and the angular dependence of the dHvA frequencies is in good agreement with the calculated results.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
Yoshiki J. Sato, Fuminori Honda, Jiri Pospisil, Ai Nakamura, Michal Valiska, Yusei Shimizu, Arvind Maurya, Yoshiya Homma, Dexin Li, Vladimir Sechovsky, Hisatomo Harima, Dai Aoki
Summary: This study investigates the single-crystal growth and Fermi surface of LaPd2Si2 as a non-magnetic reference for the pressure-induced heavy-fermion superconductor CePd2Si2. High-quality single crystals of LaPd2Si2 were successfully grown using the floating zone method and clear dHvA signals were detected. The experimental results show good agreement with the theoretical band structure calculations based on the localized-4f electron model, indicating that the 4f electrons in CePd2Si2 are itinerant.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
Hiroki Fujibayashi, Katsuki Kinjo, Genki Nakamine, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki
Summary: In this study, the static and dynamic magnetic properties of the uranium-based superconductor UTe2 were investigated using NMR measurements. The results showed that magnetic fluctuations in different crystalline axes of UTe2 are derived from the nuclear spin-lattice relaxation rate 1/T1. The magnetic fluctuations become anisotropic below 40 K and are determined by the dominant ferromagnetic fluctuations in the two-leg ladder formed by U atoms.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
Hiroki Matsumura, Hiroki Fujibayashi, Katsuki Kinjo, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki
Summary: Spin susceptibility in the superconducting state of uranium-based superconductor UTe2 was measured. The higher-quality sample exhibited a higher Tc and a narrower NMR linewidth compared to the previous sample. A significant reduction in Knight shift along the a axis was observed, which differed from the previous results along the alpha axis. The origin of these differences and the possible implications for the superconducting state were discussed.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
Arvind Maurya, Hisatomo Harima, Fuminori Honda, Yusei Shimizu, Yoshiki J. Sato, Ai Nakamura, Dexin Li, Yoshiya Homma, Dai Aoki
Summary: In this study, we observed bulk superconductivity in LaNiZn below Tc = 1.5 K, as confirmed by its electrical transport and specific heat capacity (Delta Cel/gamma Tc = 1.41). The upper critical fields along the hexagonal crystallographic c-axis and in the basal plane at 30 mK were found to be 0.36 and 0.24 T, respectively, suggesting mainly an orbital mechanism for field-induced depairing and a negligible spin triplet component in the superconducting order parameter. The angular dependence of Hc2 is explained by an effective mass model with an oblate-shaped effective Fermi surface. Our experimental and band calculation under local density approximation results suggested that LaNiZn is a Bardeen- Cooper-Schrieffer s-wave-type superconductor in the dirty limit, possibly involving multiple bands.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
A. Rosuel, C. Marcenat, G. Knebel, T. Klein, A. Pourret, N. Marquardt, Q. Niu, S. Rousseau, A. Demuer, G. Seyfarth, G. Lapertot, D. Aoki, D. Braithwaite, J. Flouquet, J. P. Brison
Summary: The recently discovered superconductor UTe2, with a superconducting transition temperature Tc between 1.5 and 2 K, has raised great attention due to its strong suspicion of spin-triplet and topological superconductivity. The properties of UTe2 under a magnetic field are also remarkable, showing field-reinforced and field-induced superconducting phases. This study provides the first complete thermodynamic determination of the phase diagram for fields applied along different crystallographic directions, revealing a strong negative curvature of the upper critical field along the easy axis and the existence of a phase transition line within the superconducting phase.
Article
Materials Science, Multidisciplinary
Arvind Maurya, Atsushi Miyake, Hisashi Kotegawa, Yusei Shimizu, Yoshiki J. Sato, Ai Nakamura, Dexin Li, Yoshiya Homma, Fuminori Honda, Masashi Tokunaga, Dai Aoki
Summary: We report the single-crystal growth of UNi4P2 and demonstrate its Ising-type ferromagnetism with a Curie temperature of 25 K through magnetization, electrical transport, and specific heat measurements. The strong anisotropy between the c axis and the tetragonal basal plane is maintained up to 57 T, while the intraplane anisotropy gradually disappears at higher fields. Our findings suggest that anisotropic electron correlations may stabilize Ising-type ferromagnetic order in one dimension at nonzero temperatures, potentially with its own characteristic universality class.
Article
Materials Science, Multidisciplinary
K. Kinjo, H. Fujibayashi, S. Kitagawa, K. Ishida, Y. Tokunaga, H. Sakai, S. Kambe, A. Nakamura, Y. Shimizu, Y. Homma, D. X. Li, F. Honda, D. Aoki, K. Hiraki, M. Kimata, T. Sasaki
Summary: UTe2 is a recently discovered spin-triplet superconductor with a magnetic field (H)-boosted superconductivity >16 T when H is applied exactly parallel to the b axis. The high-H superconducting (HHSC) phase of UTe2 has not been thoroughly investigated, and its SC properties as well as the spin state are not well understood. In this study, AC magnetic susceptibility and nuclear magnetic resonance measurements were performed, revealing that the HHSC state has bulk nature and is sensitive to the H angle, with different SC character compared to the low-H superconducting (LHSC) state. The dominant spin component of the spin-triplet pair also changes from the LHSC state (along the a axis) to the HHSC state (along the b axis). Our findings suggest that the H-induced multiple SC states originate from the remaining spin degrees of freedom.
Article
Chemistry, Physical
Shin-ichi Fujimori, Ikuto Kawasaki, Yukiharu Takeda, Hiroshi Yamagami, Norimasa Sasabe, Yoshiki J. Sato, Ai Nakamura, Yusei Shimizu, Arvind Maurya, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki
Summary: In this study, the electronic structure of f-based superconductor CeIr3 was investigated using photoelectron spectroscopy. The results showed that the Ce 4f states were mainly distributed near the Fermi energy, indicating their itinerant character and significant contribution to the density of states at the Fermi energy.
ELECTRONIC STRUCTURE
(2023)
Article
Materials Science, Multidisciplinary
Ikuto Kawasaki, Kazuharu Takeuchi, Shin-ichi Fujimori, Yukiharu Takeda, Hiroshi Yamagami, Etsuji Yamamoto, Yoshinori Haga
Summary: Angle-resolved photoemission spectroscopy (ARPES) experiments were performed to investigate the electronic structure of the heavy-fermion superconductor UPt3. The band structure of UPt3 was compared with density-functional calculations for ThPt3, and it was found that ThPt3 calculations provided a better description of the experimental band structure except for the heavy quasiparticle bands derived from 5f orbitals. The heavy quasiparticle bands were found to be renormalized by electron correlation effects and showed little temperature dependence.
