Article
Materials Science, Multidisciplinary
Mansour Mohamed, A. Sedky, Abdullah S. Alshammari, Z. R. Khan, M. Bouzidi, M. Gandouzi
Summary: The structural, optical, and photocatalytic properties of Zn1-xBixO samples (0.00 < x < 0.20) were investigated. Increasing the Bi content to 0.20 led to an increase in the a-parameter, unit cell volume, crystallite size, and porosity, while the c-parameter decreased. Adding Bi to ZnO increased the Young and bulk modulus, and all samples exhibited brittleness. Optical analysis showed that all Zn1-xBixO samples had two direct band gaps (Eg1/Eg2), with values decreasing up to 0.10 Bi content and then increasing up to 0.20 Bi. Introducing Bi3+ ions increased the reflective index of ZnO. Photocatalytic activity was reduced by 0.025 Bi doping but enhanced by increasing the Bi content to 0.20. These findings suggest that Zn1-xBixO nanoparticles are more suitable for optoelectronic devices and water purification.
Article
Engineering, Electrical & Electronic
Hafiz Muhammad Ahsan, Kanhya Lal, Murtaza Saleem, Ghulam M. Mustafa, Muhammad Ahmad Khan, Ahmed S. Haidyrah, Shahid Atiq
Summary: The synthesis of pure ZnO with nominal Mn and Co co-doping was conducted using a cost-effective wet chemical route to explore their dielectric response. Structural and morphological analysis showed the influence of Mn and Co doping on crystal structure and particle morphology in ZnO. The higher dielectric constant observed was attributed to the presence of oxygen vacancies generated during the process.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Materials Science, Ceramics
Puneet Kaur, Atul Khanna
Summary: Powder samples containing 1 mol% Re2O3/MnO and 99 mol% MAl2O4 (Re = Eu, Sm, Dy, Er and M = Ca and Sr) were prepared by solid state sintering at temperatures ranging from 1386 to 1450 ℃. The samples showed different structural, thermal, and photoluminescence properties, with calcium aluminate samples exhibiting higher luminescence intensity and quantum yield compared to strontium aluminates. Additionally, strontium aluminate samples displayed a reversible monoclinic to hexagonal structural phase transition during the heating cycle at 688℃.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Ranjita Misra, Manasi Das, Pronama Biswas, Anima Nanda
Summary: The development of Mn-doped ZnO nanocrystals successfully combines drug delivery and diagnosis. These nanocrystals exhibit nanometer range and fluorescence property, showing cytotoxic effects on tumor cells that can be eliminated by coating with a polymer. Moreover, surface conjugation of epidermal growth factor antibody on the nanocrystals enhances targeted delivery.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Materials Science, Ceramics
M. Secu, A. Kuncser, C. Negrila, A. M. Rostas
Summary: Europium-doped chlomborate BaO-B2O3-BaCl2 glasses and glass-ceramics with embedded BaCl2 nanocrystals have been synthesized, investigated, and compared with nanocrystalline powders. Structural analysis revealed the formation of BaCl2 nanocrystals in the glass and glass-ceramic, with distortion of the crystalline cell due to growth processes. Photoluminescence spectra showed the presence of Eu3+ and Eu2+ luminescent ions in the glass-ceramic, with only Eu2+ incorporated within the BaCl2 nanocrystalline phase.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Natalia Pawlik, Barbara Szpikowska-Sroka, Tomasz Goryczka, Joanna Pisarska, Wojciech A. Pisarski
Summary: In this study, Tb3+/Eu3+ co-doped xerogels and glass-ceramics containing CaF2 nanocrystals were prepared and characterized, with in situ formation of fluoride crystals verified by XRD and TEM. The study of Tb3+/Eu3+ energy transfer process was conducted through excitation and emission spectra, showing varying ET efficiencies due to different molar ratios and interionic distances. The presence of luminescence bands for both Tb3+ and Eu3+ ions under NUV excitation was observed, indicating their mutual coexistence and the effect of co-doping on fluorescence lifetimes.
Letter
Chemistry, Multidisciplinary
Jia-Min Lai, Muhammad Umair Farooq, Yu-Jia Sun, Ping-Heng Tan, Jun Zhang
Summary: The multiphonon process is crucial for understanding the electron-phonon coupling in solids, which affects their optical and transport properties. This study investigates the characteristics of high-order Raman scattering and hot luminescence in Mn-doped ZnO nanowires to shed light on the multiphonon-involved decay process of excited states, providing insights for further studies on the statistical characteristics of excited state decay.
Article
Chemistry, Physical
R. Gopalakrishnan, R. Kabilan, M. Ashokkumar
Summary: In this study, zinc-nickel-manganese oxide nanoparticles were synthesized and characterized. The presence of manganese doping was found to influence the cell parameters and shift the Zn-O absorption peak. The magnetization of the nanoparticles was enhanced by the simultaneous addition of nickel and manganese, while the antibacterial properties of the nanoparticles were demonstrated against both Gram-positive and Gram-negative bacterial strains.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Chemistry, Physical
Yogesh Kumar, S. Tripathi, Mangla Nand, R. Jangir, V. Srihari, A. Das, R. Singh, U. Deshpande, S. N. Jha, A. Arya
Summary: This study investigated the effect of Nd doping on the structural, optical, and electronic properties of lanthanum monazite structure. Pure and Nd-doped LaPO4 powders were prepared and analyzed for their composition, oxidation states, crystal structure, and bandgaps. The results confirmed the successful substitution of Nd in the LaPO4 matrix and provided insights into the local structure using extended X-ray absorption fine structure analysis.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Nguyen Thanh Phuong, Nguyen Long Giang, Dang Huu Phuc, Nguyen Ngoc Diem
Summary: Luminescent Mn-doped ZnO nanoparticles and poly(vinyl alcohol) capped Mn-doped ZnO nanocomposite materials were successfully synthesized. The diffraction peaks of Mn-doped ZnO NPs were slightly shifted compared to undoped-ZnO NPs, while the nanocomposite showed a systematic shift of XRD peaks. The luminescent materials exhibited strong fluorescence in the visible wavelength range and near-infrared emission due to XRD peak shift and defect state transitions. These materials have potential applications in light-emitting devices.
Article
Materials Science, Ceramics
G. Padmasree, P. Yadagiri Reddy, Ch. Gopal Reddy
Summary: This paper presents investigations on the effect of Dysprosium (Dy) on the structural and electrical properties of polycrystalline Yttrium Iron Oxide (YFeO3). Samples with different Dy concentrations were prepared through the sol-gel process. The results show that the lattice parameter values increase with an increase in Dy concentration, indicating changes in the crystal structure. The morphology of the samples observed through SEM reveals irregular and non-homogeneous grain sizes. The electrical properties analysis suggests an increase in leakage current density up to a certain concentration of Dy, followed by a decrease.
CERAMICS INTERNATIONAL
(2022)
Article
Multidisciplinary Sciences
Lina Chong, Guoping Gao, Jianguo Wen, Haixia Li, Haiping Xu, Zach Green, Joshua D. Sugar, A. Jeremy Kropf, Wenqian Xu, Xiao-Min Lin, Hui Xu, Lin-Wang Wang, Di-Jia Liu
Summary: The discovery of a nanofibrous cobalt spinel catalyst codoped with lanthanum and manganese provides a promising alternative to iridium for the oxygen evolution reaction (OER) in proton exchange membrane water electrolyzers (PEMWE) and reduces the cost of green hydrogen production. The catalyst demonstrates low overpotential and degradation, making it suitable for long-term use in acidic electrolyte. A PEMWE utilizing this catalyst at the anode achieves high current density and shows low degradation in accelerated stress tests.
Article
Chemistry, Physical
Mohamad Hasan Aleinawi, Ameen Uddin Ammar, Merve Buldu-Akturk, Nur Selin Turhan, Shankari Nadupalli, Emre Erdem
Summary: Transition-metal-doped ZnO is a potential dilute magnetic semiconductor for spintronic applications. This report presents the synthesis of manganese-doped ZnO using a microwave-assisted hydrolysis technique, and investigates the defect structure via electron paramagnetic resonance and photoluminescence techniques, revealing that Mn2+ dominates the intrinsic defect species in ZnO.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Metallurgy & Metallurgical Engineering
Emine Guneri, Johnson Henry, Fatma Gode, Nilgun Kalaycioglu Ozpozan
Summary: Pure ZnO and Mn-doped ZnO thin films were prepared by chemical bath deposition method with various Mn doping concentrations. The structural, morphological, and optical properties of the films were analyzed using different techniques. XRD analysis revealed hexagonal structured ZnO in all films, with a peak shift observed in Mn-doped films. The crystallite size increased with Mn doping. The surface morphology of Mn-doped films exhibited irregularly shaped agglomerated particles. The transmittance spectra showed higher transmittance in the visible region, which decreased with Mn doping, indicating increased optical absorption. The band gap of Mn-doped films decreased with Mn doping. Mn-doped films exhibited higher optical and electrical conductivity in the UV region.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Chemistry, Physical
Warda Darenfad, Noubeil Guermat, Kamel Mirouh
Summary: Pure ZnO, Zn0.97Mg0.03O, Zn0.96Mg0.03Mn0.01O, and Zn0.90Mg0.03Mn0.01F0.06O nanocrystalline thin films were successfully prepared using the spray pyrolysis method. The structural properties were characterized using XRD, SEM, UV-Visible spectrophotometry, and Hall effect measurement technique. The doped thin films exhibited higher transmission spectra and a shift towards lower wavelengths compared to pure ZnO, with Zn0.97Mg0.03O film having a band gap of 3.31 eV. The Zn0.90Mg0.03Mn0.01F0.06O thin film showed a low electrical resistivity and superior photoelectric performance, making it a promising candidate for optoelectronic devices.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Chemistry, Multidisciplinary
Zhenyu Wang, Zhanyang Hao, Yayun Yu, Yuan Wang, Shiv Kumar, Xiangnan Xie, Mingyu Tong, Ke Deng, Yu-Jie Hao, Xiao-Ming Ma, Ke Zhang, Cai Liu, Mingxiang Ma, Jiawei Mei, Guang Wang, Eike F. Schwier, Kenya Shimada, Fufang Xu, Chang Liu, Wen Huang, Jianfeng Wang, Tian Jiang, Chaoyu Chen
Summary: This study reports the realization of moire Dirac cones in a monolayer In2Se3/bilayer graphene heterostructure, showing direct observation of Fermi velocity reduction and suggesting strong In2Se3/graphene interlayer coupling.
ADVANCED MATERIALS
(2021)
Article
Physics, Applied
Mahima Singh, Shiv Kumar, Mohd Alam, Vinod K. Gangwar, Labanya Ghosh, Debarati Pal, Rahul Singh, P. Shahi, P. Chaudhary, Kenya Shimada, Sandip Chatterjee
Summary: The study on Bi2-xMx(SeS)(3) with Fe and Mn doping reveals different magnetic ordering mechanisms, showing the potential for spintronic applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Condensed Matter
P. J. Grenz, D. Thonig, M. Holtmann, K. Miyamoto, S. Kumar, E. Schwier, T. Okuda, J. Henk, M. Donath
Summary: Through a combined experimental and theoretical study, it was found that Fe and Co adlayers on the W(110) surface can significantly affect the energy shift of the Dirac-type surface state (DSS), with structural changes and surface potential alterations being contributing factors.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Physics, Condensed Matter
Khyati Anand, Arkadeb Pal, Mohd. Alam, Sambhab Dan, Shiv Kumar, Surajit Ghosh, Seema Kumari, A. Das, Masahiro Sawada, Anita Mohan, Vasant G. Sathe, Sandip Chatterjee
Summary: The double perovskite compound Tb2CoMnO6 exhibits both anti-ferromagnetic and ferromagnetic phases, coexisting due to the presence of anti-site disorder (ASD) that leads to spin frustration and the re-entrant cluster glass state at low temperatures. The coupling between phononic degree of freedom and spin has also been observed in the system. The experimental behavior is consistent with theoretical calculations.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Physics, Applied
Sambhab Dan, Shiv Kumar, Shovan Dan, Debarati Pal, S. Patil, Abhineet Verma, Satyen Saha, Kenya Shimada, S. Chatterjee
Summary: Previous studies have observed a broad peak in the temperature dependent resistivity in Cu substituted Bi2Te3, but its origin is still unclear. Our investigation reveals that an electronic phase transition accompanied by tuning of the Fermi level primarily contributes to the observed resistivity behavior. We have proposed a model to demonstrate how the bandgap affects the resistivity, and our findings suggest that bulk carriers play a significant role in producing the observed resistivity behavior, as supported by various experimental techniques.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Shaosheng Yue, Hui Zhou, Ya Feng, Yue Wang, Zhenyu Sun, Daiyu Geng, Masashi Arita, Shiv Kumar, Kenya Shimada, Peng Cheng, Lan Chen, Yugui Yao, Sheng Meng, Kehui Wu, Baojie Feng
Summary: This study investigates the existence and properties of one-dimensional Dirac fermions in Si nanoribbons (SiNRs) through various experimental and theoretical approaches. The results provide a theoretical explanation and establish SiNRs as a platform for studying one-dimensional Dirac materials.
Article
Chemistry, Multidisciplinary
Zhenyu Sun, Hui Zhou, Cuixiang Wang, Shiv Kumar, Daiyu Geng, Shaosheng Yue, Xin Han, Yuya Haraguchi, Kenya Shimada, Peng Cheng, Lan Chen, Youguo Shi, Kehui Wu, Sheng Meng, Baojie Feng
Summary: The presence of a breathing kagome lattice in Nb3Cl8 leads to a band gap, but the topological flat bands (TFBs) are preserved. Through experimental observation and computational analysis, we confirm the existence of TFBs and a moderate band gap in Nb3Cl8. Mechanical exfoliation successfully yields stable monolayer Nb3Cl8 under ambient conditions. Additionally, calculations reveal a magnetic ground state in monolayer Nb3Cl8, offering opportunities to study the interplay between geometry, topology, and magnetism.
Article
Physics, Applied
Mahima Singh, Labanya Ghosh, Vinod K. Gangwar, Yogendra Kumar, Debarati Pal, P. Shahi, Shiv Kumar, Sudip Mukherjee, K. Shimada, Sandip Chatterjee
Summary: The magneto-transport and ARPES of the S-doped Bi1.5Sb0.5Te1.3Se1.7 system were investigated, and both pMR and nMR, as well as a transition from WAL to WL, were observed. The interplay between pMR and nMR was elucidated, and the topological surface state bands were explored using ARPES.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Xueyao Hou, Mansuer Wumiti, Shiv Kumar, Kenya Shimada, Masahiro Sawada
Summary: In this study, the electronic structure of the Cr2O3/graphene interface was investigated using first-principles calculations and experimental techniques. It was found that the mid-gap states are sensitive to the adsorption type of graphene and can be switched by changing the substrate magnetization direction.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Anup Pradhan Sakhya, Shiv Kumar, Arindam Pramanik, Ram Prakash Pandeya, Rahul Verma, Bahadur Singh, Sawani Datta, Souvik Sasmal, Rajib Mondal, Eike F. Schwier, Kenya Shimada, A. Thamizhavel, Kalobaran Maiti
Summary: Studied the behavior of nontrivial Dirac fermion states in the antiferromagnetic metal SmBi. Experimental results showed the existence of multiple Fermi pockets and band inversion. In addition, Dirac cones were found within the energy gap of the bulk bands. The Fermi surface constituted by the surface states was destroyed near the Néel temperature.
Article
Materials Science, Multidisciplinary
Amit Kumar, Shiv Kumar, Yudai Miyai, Kenya Shimada
Summary: This study investigates the temperature-dependent band structure and energy dependence of the electron-phonon interaction of the topological surface state (TSS) on the three-dimensional topological insulator Bi2Te3 using angle-resolved photoemission spectroscopy. The findings reveal that the degeneracy at the Dirac point (DP) remains robust with increasing temperature, indicating topological protection. Additionally, the electron-phonon coupling parameter is shown to depend on the initial-state electron energy.
Article
Materials Science, Multidisciplinary
Marcel Holtmann, Peter Krueger, Koji Miyamoto, Taichi Okuda, Pascal J. Grenz, Shiv Kumar, Kenya Shimada, Markus Donath
Summary: Tamm and Shockley states are used to describe surface states in different crystal systems. By studying the electronic surface states on the Re(0001) surface, we found that spin-orbit interaction can generate a double W-shaped energy vs k11 dispersion. We developed verifiable criteria to distinguish between these two types of surface states and provided a consistent explanation for the role of spin-orbit interaction in this scenario.
Article
Materials Science, Multidisciplinary
A. Estyunin, E. F. Schwier, S. Kumar, K. Shimada, K. Kokh, O. E. Tereshchenko, A. M. Shikin
Summary: Contemporary studies of magnetic topological insulators require accurate measurements to investigate Dirac point gaps. In this study, the effect of band energy shift due to sample contamination and irradiation on electronic structure measurement using ARPES method is examined. The results show that the shifted topological surface state remains stable and can be used to store information, but it becomes significantly broadened and its intensity drops under irradiation.
Article
Materials Science, Multidisciplinary
Shailja Sharma, Shiv Kumar, Girish C. Tewari, Girish Sharma, Eike F. Schwier, Kenya Shimada, A. Taraphder, C. S. Yadav
Summary: The researchers conducted magnetotransport and ARPES measurements on PdxBi2Te3 single crystals and discovered the reduction of magnetoresistance and mobility upon Pd doping, as well as the presence of TSSs confirmed by SdH oscillations. Hall measurement and ARPES measurements also revealed the change in charge carrier type and band structure induced by Pd doping.
Article
Materials Science, Multidisciplinary
Vinod K. Gangwar, Shiv Kumar, Mahima Singh, Debarati Pal, Labanya Ghosh, Prajyoti Singh, Zhang Yufeng, Chaoyu Chen, Eike F. Schwier, Kenya Shimada, Prashant Shahi, Yoshiya Uwatoko, Swapnil Patil, Anup K. Ghosh, Sandip Chatterjee
Summary: The study investigated the different roles of surface and bulk states in Bi1.9Dy0.1Te3 topological insulators through electronic states, magnetotransport properties, Seebeck coefficient, and magnetization. A significant magnetoresistance value of around 1500% at a magnetic field of 7T was attributed to the surface state. The magnetization behavior indicated the presence of an antiferromagnetic state, while the observed anomalous Hall effect was established as the contribution from the bulk state.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
