Article
Nanoscience & Nanotechnology
Vahagn Mkhitaryan, Eduardo J. C. Dias, Fabrizio Carbone, F. Javier Garcia de Abajo
Summary: Recent advances in ultrafast electron microscopy have enabled the combination of optical pumping of nanostructures and electron beam probing with sub-Angstrom and femtosecond spatiotemporal resolution. This technique is predicted to reveal the rich out-of-equilibrium dynamics of plasmon excitations in graphene and graphite samples. By measuring angle-resolved, energy-integrated inelastic electron scattering, it is possible to track the temporal evolution of plasmons in these structures and provide momentum-resolved mode identification.
Article
Materials Science, Multidisciplinary
N. N. Badr, F. Long, Y. Luo, M. Topping, L. K. Beland, Z. Yao, L. Balogh, M. R. Daymond
Summary: The crystal structure of the interfacial areas of a water-quenched nano-hydride was characterized using electron energy-loss spectroscopy and electron diffraction. Plasmon energy values of 17.4±0.01 eV and 18.3±0.01 eV were observed in the interfacial area, but the existence of the ζ- and γ-phases was ruled out. Simulations suggested that the observed energy values could be attributed to the delocalized nature of plasmon vibration and the effect of the interface on shifting the plasmon vibration frequency.
Article
Physics, Multidisciplinary
Na Qin, Xian Du, Yangyang Lv, Lu Kang, Zhongxu Yin, Jingsong Zhou, Xu Gu, Qinqin Zhang, Runzhe Xu, Wenxuan Zhao, Yidian Li, Shuhua Yao, Yanfeng Chen, Zhongkai Liu, Lexian Yang, Yulin Chen
Summary: In this study, the electronic structure of Cu2TlX (2) (X = Se, Te), ternary transition metal chalcogenides with quasi-two-dimensional crystal structure, is investigated using angle-resolved photoemission spectroscopy and ab initio calculation. The band dispersions near the Fermi level are mainly contributed by the Te/Se p orbitals. According to the ab initio calculation, the electronic structure changes from a semiconductor with indirect band gap in Cu2TlSe2 to a semimetal in Cu2TlTe2, suggesting a band-gap tunability with the composition of Se and Te. Comparing the experimental data with the calculated results, strong modulation of the band structure by spin-orbit coupling in the compounds is identified.
Article
Materials Science, Multidisciplinary
Philipp Hans, Cristian Mocuta, Marie-Ingrid Richard, Daniel Benoit, Philippe Boivin, Yannick Le-Friec, Roberto Simola, Olivier Thomas
Summary: This study investigates the effects of hydrogen treatment on the crystallization behavior of N-doped, Ge-rich Ge2Sb2Te5 phase-change materials for memory applications. The results show that hydrogen treatment lowers the crystallization temperature of Ge2Sb2Te5 cubic phase and promotes the formation of the trigonal phase in thin films.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Microscopy
Janis Koester, Alexander Storm, Tatiana E. Gorelik, Michael J. Mohn, Fabian Port, Manuel R. Goncalves, Ute Kaiser
Summary: In this study, the signature of mono- and few-layer MoS2 and MoTe2 was systematically evaluated using TEM methods. The number of layers was determined by comparing the results of three TEM methods and discussing their strengths and limitations.
Article
Physics, Applied
Chung Koo Kim, Jonathan D. Denlinger, Asish K. Kundu, Genda Gu, Tonica Valla
Summary: Magnetism disrupts the time-reversal symmetry in 3D topological insulators, leading to the quantum anomalous Hall effect and the opening of a Dirac gap. The discrepancy between the low temperature quantum anomalous Hall effect and the large Dirac gap found in magnetic topological insulators remains puzzling. Angle-resolved photoemission spectroscopy was used to study the surface electronic structure of Cr0.15(Bi0.1Sb0.9)1.85Te3, revealing a gapless surface state in contrast to tunneling studies reporting a large Dirac gap.
JOURNAL OF APPLIED PHYSICS
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
H. Sugimoto, K. Nishimura, H. Tabata
Summary: This study reports the experimental and calculated results of the THz surface plasmon resonance (THz-SPR) of (Bi, Sb)(2)(Se, Te)(3) for the first time. It is found that the bulk electron influence in the band structure has a small contribution to the surface plasmon resonance, and Bi2Se3 has the highest Q value among graphene or topological insulators below 1 THz.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)
Article
Chemistry, Multidisciplinary
Gopabandhu Panigrahi, Sweta Yadav, Subhendu Jana, Arghya Ghosh, Manish K. Niranjan, Jai Prakash
Summary: Two new mixed metal ternary chalcogenides, NaScSe2 and NaScTe2, were synthesized in this study. The compounds were found to be semiconductors with optical bandgap values confirming their nature. Several properties like optical absorption, thermal conductivity, and emission spectroscopic analysis were investigated, along with DFT calculations to study their electronic structure and chemical bonding properties.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Microscopy
Proloy Nandi, Eric R. Hoglund, James M. Howe
Summary: Spatially resolved valence electron energy-loss spectroscopy was used to acquire low-loss EEL spectra from Al grain boundaries with different GB energies. Three different separation techniques were employed to extract the GB response from the spectra and produced similar results.
Article
Chemistry, Physical
Weidi Zhang, Shuang Liu, Qilong Ren, Ruyu Tu, Fenhui Qiu, Shihong Xu, Wei Sun, Mengjie Tian
Summary: The study found that N,N-bis(2-hydroxy-3-chloropropyl) dodecylamine (BHCPDA) has better selectivity in the reverse flotation of apatite and quartz compared to dodecylamine (DDA). Zeta potential experiments and X-ray photoelectron spectroscopy analysis showed that BHCPDA has a greater adsorption amount on quartz surface than on apatite surface, explaining its higher ability to collect quartz. However, BHCPDA also had a higher adsorption amount on apatite surface than DDA, indicating that the efficacy of flotation collectors is not solely dependent on their adsorption amounts on mineral surfaces.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Ceramics
Fei-Hung Lin, Chia-Jyi Liu
Summary: Bi2Te3-based thermoelectric materials are the largest segment of sales in thermoelectric products. In this study, we propose an energy-efficient synthesis method conforming to the 6th principle for green chemistry to manufacture Bi2Te3-based thermoelectric materials. By studying the formation mechanism of n-Bi2Te3 nanocomposites synthesized at room temperature, we found that nanosized Bi and Te would first form before the growth of n-Bi2Te3. To shorten the growth period, we developed a procedure using nanosized precursors of Bi, Sb, and Te, followed by heat treatment. The resulting zT values were 1.27 at 400 K for p-(Bi, Sb)(2)Te-3-Te composite and zT = 1 for n-Bi2Te3 at 425 K.
CERAMICS INTERNATIONAL
(2023)
Article
Biochemistry & Molecular Biology
Sabir A. Mohammed Salih, Huda A. Basheer, Jesus Vicente de Julian-Ortiz, Haydar A. Mohammad-Salim
Summary: This study investigated the [3+2] cycloaddition reactions of N-methyl-C-4-methyl phenyl-nitrone 1 and 2-propynamide 2 using molecular electron density theory. The reactions produced four different products through irreversible pathways. The formation of cycloadduct 6 had a slightly increased polar character, observed through global electron density transfer.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Inorganic & Nuclear
Marjaana Taimisto, Tom Bajorek, J. Mikko Rautiainen, Tapani A. Pakkanen, Raija Oilunkaniemi, Risto S. Laitinen
Summary: The pathways to the formation of a series of [RuCl2(CO)(2)(ERR ')(2)] complexes have been explored experimentally and computationally. The results show that the reaction rate is faster in THF and the highest yield is observed for the telluroether complexes. The nature of the solvent does not affect the reaction path. The substitution of one CO ligand by the second ERR ' is the rate-determining step. The formation of [RuCl2(CO)(3)(THF)] is observed in THF, but it is not necessary for the dissociation of [RuCl2(CO)(3)](2).
DALTON TRANSACTIONS
(2022)
Article
Optics
Shufang Gao, Zheng Zhang, Bingxuan Li, Jun Feng
Summary: The Bi2Te3/Sb2Te3-Graphene (BTST-G) bidirectional heterostructures (BHSs) are constructed for the first time by a self-assembly solvothermal method, which overcome the application limitations of individual 2D materials. The BHSs combine the advantages of BTST and graphene, making them excellent absorbers for ultra-short-pulse laser technology.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
N. P. Stepina, A. O. Bazhenov, A. V. Shumilin, A. Yu. Kuntsevich, V. V. Kirienko, E. S. Zhdanov, D. V. Ishchenko, O. E. Tereshchenko
Summary: In this study, magneto-resistance measurements were conducted in (Bi, Sb)2(Te, Se)3 3D topological insulator thin films grown on Si(111) substrate, revealing anomalous weak antilocalization effects and non-linear weak magnetic field Hall effect. A two-liquid model was used to explain both transport features, suggesting a possible correlation with the Zeeman-field-induced gap opening mechanism.
Article
Nanoscience & Nanotechnology
David A. Garfinkel, Vasudevan Iyer, Robyn Seils, Grace Pakeltis, Marc R. Bourgeois, Andrew W. Rossi, Clay Klein, Benjamin J. Lawrie, David J. Masiello, Philip D. Rack
Summary: Trimer meta-atoms composed of three gold rods were fabricated and their near-field plasmonic responses were characterized. The magnetic and electric modes of the trimer structure could be tuned by changing the length of the rods. The study also found that the intensity of the electric mode increased more than expected, while the magnetic mode showed the expected tilt dependence. This research opens up new possibilities for studying the nanoscale excited-state of other magnetic meta-atom structures.
ACS APPLIED NANO MATERIALS
(2022)
Article
Physics, Multidisciplinary
Marc R. Bourgeois, Elliot K. Beutler, Siamak Khorasani, Nicole Panek, David J. Masiello
Summary: Exciton polaritons are important light-matter excitations with potential applications. By using lattice electron energy gain spectroscopy, the characteristics of EPs in nanoscale structured cavities can be measured.
PHYSICAL REVIEW LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Jingyang He, Seng Huat Lee, Francesco Naccarato, Guillaume Brunin, Rui Zu, Yuanxi Wang, Leixin Miao, Huaiyu Wang, Nasim Alem, Geoffroy Hautier, Gian-Marco Rignanese, Zhiqiang Mao, Venkatraman Gopalan
Summary: This study reports the bulk single crystals of SnP2S6 with a large nonlinear optical susceptibility, a large laser-induced damage threshold, and a wide transparency range, making it an outstanding candidate for infrared laser applications.
Article
Chemistry, Multidisciplinary
Chenhui Yan, Yanglin Zhu, Leixin Miao, Sebastian Fernandez-Mulligan, Emanuel Green, Ruobing Mei, Hengxin Tan, Binghai Yan, Chao-Xing Liu, Nasim Alem, Zhiqiang Mao, Shuolong Yang
Summary: Researchers have discovered tunable magnetic ground states in MnBi6Te10 by using magnetization measurements, angle-resolved photoemission spectroscopy, and transmission electron microscopy. They have demonstrated an energy gap at the Dirac point on the MnBi2Te4 termination in the ferromagnetic phase, and gapless topological surface states on all terminations in the antiferromagnetic MnBi6Te10. By analyzing the data, they have proposed a conceptual framework to explain how these defects can affect the overall magnetic ground state energy and be used to tune the magnetic topological orders.
Article
Chemistry, Multidisciplinary
Marc R. Bourgeois, Austin G. Nixon, Matthieu Chalifour, Elliot K. Beutler, David J. Masiello
Summary: Free-electron-based measurements in scanning transmission electron microscopes (STEMs) provide valuable information on the broadband spectral responses of nanoscale systems with subdiffraction limited spatial resolution. Recent advances in manipulating the spatial phase profile of electron wavefronts enable theoretical descriptions of interactions between electron probes and optically stimulated nanophotonic targets. By leveraging phase shaping techniques, nanospectroscopy can be used to probe the polarization-resolved response field of optically excited targets with nanoscale spatial resolution. These developments have the potential to become powerful tools for fundamental studies of quantum materials, noninvasive imaging, and nanoscale 3D field tomography.
Article
Multidisciplinary Sciences
Leixin Miao, Kishwar-E Hasin, Parivash Moradifar, Debangshu Mukherjee, Ke Wang, Sang-Wook Cheong, Elizabeth A. Nowadnick, Nasim Alem
Summary: In this study, the authors directly observed double bilayer polar nanoregions in Ca2.9Sr0.1Mn2O7 using aberration-corrected scanning transmission electron microscopy. Electron energy loss spectroscopy studies and first-principles calculations revealed that the stabilization mechanism of the nanoregions is directly related to a change in the oxidation state of manganese, which is linked to the presence of manganese antisite defects.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Marc R. Bourgeois, Andrew W. Rossi, Siamak Khorasani, David J. Masiello
Summary: This study investigates the photothermal properties of surface lattice resonances (SLRs) in periodic arrays of plasmonic nanoparticles through analytical theory and numerical calculations. It shows that steady-state thermal gradients ranging from nanoscale to hundreds of microns can be actively controlled using light, and unexpected thermal responses can be achieved in topologically non-trivial SLR lattices.
Article
Chemistry, Physical
Claire A. West, Stephen A. Lee, Jesse Shooter, Emily K. Searles, Harrison J. Goldwyn, Katherine A. Willets, Stephan Link, David J. Masiello
Summary: Although originally designed for detecting individual molecules or small nanoparticles, photothermal imaging is now used to characterize larger structures that scatter light strongly. The interpretation of the photothermal signal in this regime requires revisiting fundamental assumptions. Theoretical analyses reveal nonlinearity in the photothermal signal with pump intensity and contraction of the point spread function, and show deviations between photothermal spectra and absorption spectra at higher pump intensities. Companion experiments on gold nanoparticles confirm the theoretical predictions and demonstrate new aspects of photothermal imaging.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Feng Pan, Kristoffer Karlsson, Austin G. Nixon, Levi T. Hogan, Jonathan M. Ward, Kevin C. Smith, David J. Masiello, Sile Nic Chormaic, Randall H. Goldsmith
Summary: Active control of plasmonic-photonic interactions at the single-particle level is demonstrated using a microfluidic approach based on microbubble whispering-gallery mode cavities. By changing the solvent inside the microbubble, control can be exerted on the spatial overlap between photonic and plasmonic modes. Qualitative agreement between experiment and simulation reveals the competing roles mode overlap and mode volume play in altering coupling strengths.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Multidisciplinary Sciences
Lujin Min, Hengxin Tan, Zhijian Xie, Leixin Miao, Ruoxi Zhang, Seng Huat Lee, Venkatraman Gopalan, Chao-Xing Liu, Nasim Alem, Binghai Yan, Zhiqiang Mao
Summary: The nonlinear Hall effect (NLHE) is a new type of Hall effect with wide application prospects. Previous NLHEs have mostly been observed at low temperatures, but researchers have discovered a strong bulk NLHE at room temperature in BaMnSb2 material. This finding opens up new possibilities for wireless microwave detection and frequency doubling.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Vishal Kumar, Andrew W. Rossi, Zachary R. . Lawson, Robert D. Neal, Jordan A. . Hachtel, Svetlana Neretina, David J. Masiello, Jon P. Camden
Summary: In this study, the near-field response of individual gold nanotriangles was characterized using high-resolution electron energy-loss spectroscopy (EELS) performed inside of a scanning transmission electron microscope (STEM) over a broad spectral region. The spatial and spectral extent of each nanotriangle's plasmonic Fabry-Perot modes were imaged, and the resonance energies were measured, providing detailed information on infrared plasmon dephasing times and dispersion relations. Numerical electromagnetic simulations of the electron probe were used to interpret the experimental results and compare the near-field electromagnetic enhancement factors of gold nanotriangles and nanorods. This study provides unique insights for designing noble metal plasmonic nanoparticle systems for solar energy harvesting and sensing applications in the near-and mid-infrared.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Optics
Rana Faryad Ali, Jacob A. Busche, Saeid Kamal, David J. Masiello, Byron D. Gates
Summary: Recent research in nanophotonics has focused on the ability of nonlinear optical processes to transform optical signals in various devices. However, the weakness of optical nonlinearities at smaller scales has limited the efficiency of miniaturized devices. This study demonstrates a novel mechanism for significantly enhancing second harmonic generation through coupling to localized surface plasmon resonances. The findings suggest a new approach for designing subwavelength nonlinear optical platforms to maximize efficiency.
LIGHT-SCIENCE & APPLICATIONS
(2023)
