Article
Physics, Multidisciplinary
Yuan-Chao Hu, Hajime Tanaka
Summary: Research reveals that the low-temperature physical properties of disordered amorphous solids differ significantly from those of ordered crystalline solids. The study identifies the microscopic origin of the excess vibrational density of states, known as the 'boson peak', as quasi-localized vibrations of string-like dynamical defects.
Article
Multidisciplinary Sciences
Myungjae Lee, Hanyu Hong, Jaehyung Yu, Fauzia Mujid, Andrew Ye, Ce Liang, Jiwoong Park
Summary: This paper reports three-atom-thick waveguides, called delta waveguides, based on wafer-scale molybdenum disulfide (MoS2) monolayers, which can guide visible and near-infrared light over millimeter-scale distances with low loss and efficient in-coupling. The extreme thinness of the waveguides enables a light-trapping mechanism similar to a delta-potential well in quantum mechanics, allowing for guided waves that propagate freely along the in-plane direction but are confined along the out-of-plane direction. The integration of thin-film optical components with delta waveguides demonstrates key functionalities essential for two-dimensional photonics.
Article
Materials Science, Multidisciplinary
M. Molina-Ruiz, H. C. Jacks, D. R. Queen, T. H. Metcalf, X. Liu, F. Hellman
Summary: Specific heat measurements of hydrogenated amorphous silicon prepared by hot-wire chemical vapor deposition reveal a large density of two-level systems at low temperature. Annealing at 200 degrees C irreversibly reduces the non-Debye specific heat by an order of magnitude at 2 K, indicating a significant reduction in the density of two-level systems. The presence of hydrogen is suggested to anomalously lower the coupling constant value.
Article
Multidisciplinary Sciences
Daniel Lordan, Guannan Wei, Paul McCloskey, Cian O'Mathuna, Ansar Masood
Summary: This study focused on uncovering the origin of PMA in amorphous thin films deposited by magnetron sputtering, revealing that the change in the nature of anisotropy is related to the growth mechanism of the films and can be avoided by carefully selecting a deposition pressure regime. The emergence of PMA in amorphous thin films was found to be associated with the columnar growth of the films, which was previously not reported as a governing mechanism of perpendicular magnetisation.
SCIENTIFIC REPORTS
(2021)
Article
Multidisciplinary Sciences
Mallory Mativenga, Farjana Haque, Mohammad Masum Billah, Jae Gwang Um
Summary: Exposing amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) to deep ultraviolet light (lambda =175 nm) results in a rigid negative threshold-voltage shift, subthreshold hump, and increase in subthreshold-voltage slope, attributed to photo creation and ionization of oxygen vacancy states (V-O). The hump is caused by the highly conductive backchannel and can be suppressed by reducing the a-IGZO film thickness or applying a back bias after radiation. The instability is mainly due to ionized V-O and can be minimized by understanding and controlling the ionization process.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Rinipal Kaur, Deepanjan Bhattacharya, Ulyana S. Cubeta, Vlad Sadtchenko
Summary: When heated, glasses undergo a devitrification process that is not yet fully understood. By using a high-resolution scanning calorimetry technique, researchers have studied the softening of glassy methylbenzene films with different thicknesses. They discovered that the devitrification process starts with the formation of a softening front that propagates through the films. However, in thicker films, the front propagation continues beyond the bulk softening, leading to distinct heterogeneous devitrification processes.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Environmental Sciences
Ying Liu, Cheng Chen, Xiao Feng
Summary: This study investigates the properties of the reliable acoustic path (RAP) on a global scale. The results show that RAP range is positively correlated with ocean depth. Contrary to previous beliefs, sound speed profiles (SSPs) play a crucial role in determining RAP properties and can enhance the performance of underwater localization or communication systems.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Bing-Yue Tsui, Yen-Ling Chen, Shih-Hao Lai
Summary: In this study, metal contact with low specific contact resistance was developed on p-type SiC using fine-tuned TiAl deposition and annealing conditions. The nonuniform Ti-Si-C interfacial layer grown on high temperature ion implanted P+ SiC exhibited nonohmic behavior at small contact areas, which could be improved through low-energy, room-temperature ion implantation and Ar plasma treatment. The metal contact on p-type SiC achieved a record-low specific contact resistance at a small contact area through the aforementioned methods.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Materials Science, Ceramics
B. Swaminathan, N. R. McCarthy, A. S. Almansour, K. Sevener, A. K. Musaffar, T. M. Pollock, J. D. Kiser, S. Daly
Summary: The relationship between acoustic emission (AE) and damage source areas in SiC/SiC minicomposites was modeled using insights from in-situ tensile testing in scanning electron microscope (SEM). Damage up to matrix crack saturation was bounded by AE generated by matrix cracking (lower bound) and AE generated by matrix cracking, fiber debonding, and sliding in crack wakes (upper bound). Despite fiber debonding and sliding exhibiting lower strain energy release rates compared to matrix cracking and fiber breakage, they still contribute significantly to damage area and likely produce AE.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Engineering, Electrical & Electronic
RuHua Zhang, NianSheng Yin, Gang Wang
Summary: By analyzing the microstructure, composition, and crystallization temperature of Fe-Ni-Co amorphous ribbons using XRD, SEM, and DSC, the effects of the manufacturing process and parameters on the soft magnetic properties of the ribbons were systematically regulated and analyzed. Optimal molding process parameters were obtained through experiments and orthogonal tests. The manufacturing process can be optimized to improve the production efficiency and service characteristics of acoustic magnetic tags.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Physics, Applied
Maxim Shugaev, Leonid Zhigilei
Summary: This study demonstrates that under nonablative thermoelastic irradiation regime, laser pulses with appropriate spot size and energy deposition depth can generate high-intensity surface acoustic waves (SAWs) in Si, with strain amplitudes reaching levels of 10^-4 to 10^-3. These strong SAWs have the potential to drive nonlinear profile sharpening and shock front formation during their propagation, presenting the feasibility of continuous generation of strong nonlinear pulses of SAWs for various applications.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Karen Wilken, Mehmet Guenes, Shuo Wang, Friedhelm Finger, Vladimir Smirnov
Summary: This study investigates the effects of prolonged postdeposition annealing on the performance of low-temperature fabricated amorphous silicon (a-Si:H) solar cells. The current-voltage curves of the solar cells show substantial improvements upon annealing, primarily due to enhancements in the collection voltage. The deposition-induced modifications of the p-type layers have negligible contributions to the annealing behavior, while variations in the properties of the n-type and intrinsic layers significantly affect the annealing effect. The annealing effect mainly originates from changes in the electron mu tau-product in the intrinsic absorber layer, with a minor contribution from changes in the hole mu tau-products. Additionally, computer simulations accurately replicate the improvements in external quantum efficiency curves upon annealing by assuming an increase in the band mobilities of both electrons and holes.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Physics, Condensed Matter
Nikolas J. Podraza, David B. Saint John, Maxwell M. Junda, Robert W. Collins
Summary: Hydrogenated amorphous silicon germanium alloy films were prepared by PECVD and characterized by RTSE. The mean free path of photoelectronic excitations decreased with the addition of germanium, but increased with increased hydrogen plasma treatment.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Golekamang P. Thaganyana, John Bosco Habarulema, Chigomezyo Ngwira, Irfan Azeem
Summary: This article presents observations of medium to large-scale traveling ionospheric disturbances (TIDs) originating from high latitudes, and propagating across the equator into the opposite hemisphere in the African-European sector during geomagnetically quiet conditions between 2010 and 2018. The study identifies the characteristics of the TIDs, including their propagation velocities, periods, and wavelengths, and suggests that tertiary gravity waves from orographic forcing may be the likely source of the observed TIDs.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Engineering, Multidisciplinary
Haruki Sobue, Akira Chiba, Yifei Cai, Kyohei Kiyota, Yusuke Fujii, Kunihiro Senda, Soichiro Yoshizaki
Summary: This article fabricated three test motors with different iron materials, carried out acoustic noise analysis, and found that magnetostriction of different iron materials plays an important role in acoustic noise analysis.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2021)
Article
Physics, Multidisciplinary
Mario Motta, Chong Sun, Adrian T. K. Tan, Matthew J. O'Rourke, Erika Ye, Austin J. Minnich, Fernando G. S. L. Brandao, Garnet Kin-Lic Chan
Article
Chemistry, Physical
Alec F. White, Yang Gao, Austin J. Minnich, Garnet Kin-Lic Chan
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Multidisciplinary Sciences
Bo Sun, Shanyuan Niu, Raphael P. Hermann, Jaeyun Moon, Nina Shulumba, Katharine Page, Boyang Zhao, Arashdeep S. Thind, Krishnamurthy Mahalingam, JoAnna Milam-Guerrero, Ralf Haiges, Matthew Mecklenburg, Brent C. Melot, Young-Dahl Jho, Brandon M. Howe, Rohan Mishra, Ahmet Alatas, Barry Winn, Michael E. Manley, Jayakanth Ravichandran, Austin J. Minnich
NATURE COMMUNICATIONS
(2020)
Article
Materials Science, Multidisciplinary
Alexander Y. Choi, Peishi S. Cheng, Benjamin Hatanpaa, Austin J. Minnich
Summary: This study presents a first-principles theory of electronic noise for warm electrons in semiconductors, offering a parameter-free approach to probe the microscopic transport processes that give rise to electronic noise.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Polymer Science
Stavros X. Drakopoulos, Georgia C. Manika, Aurora Nogales, Taeyong Kim, Andrew B. Robbins, Gianfranco Claudio, Austin J. Minnich, Tiberio A. Ezquerra, Georgios C. Psarras, Ignacio Martin-Fabiani, Sara Ronca
Summary: The study reveals the impact of stretching on the structure and properties of dis-UHMWPE composites reinforced with gold nanoparticles. Stretching increases orientation and crystallinity, reduces nanoparticle aggregation, and significantly enhances thermal conductivity and resistivity.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Physics, Applied
Usama Choudhry, Taeyong Kim, Melanie Adams, Jeewan Ranasinghe, Runqing Yang, Bolin Liao
Summary: This tutorial provides an in-depth discussion of the operational principle and instrumentation details of a modern heterodyne TGS configuration and reviews recent applications of TGS in characterizing microscale transport of heat, charge, spin, and acoustic waves, with an emphasis on thermal transport.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Taeyong Kim, Saejin Oh, Usama Choudhry, Carl D. Meinhart, Michael L. Chabinyc, Bolin Liao
Summary: This study utilized scanning ultrafast electron microscopy to observe the dynamics of photoinduced transient strain in the semiconducting polymer P3HT, revealing a unique ring-shaped contrast. The unusual observation was attributed to the electronic structure modulation of P3HT caused by a photoinduced strain field. This work provides important insights into tailoring optoelectronic properties using transient mechanical deformation in semiconducting polymers.
Article
Multidisciplinary Sciences
Taeyong Kim, Stavros X. Drakopoulos, Sara Ronca, Austin J. Minnich
Summary: This article investigates the thermal conductivity and mean free path accumulation function of disentangled UHMWPE films. The experimental results show that longitudinal atomic vibrations are the primary heat carriers, and the mean free path is limited by the dimensions of extended crystals. This study is of great importance for understanding the thermal transport properties of oriented polymers.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Taeyong Kim, Soyeon Park, Vasudevan Iyer, Basamat Shaheen, Usama Choudhry, Qi Jiang, Gage Eichman, Ryan Gnabasik, Kyle Kelley, Benjamin Lawrie, Kai Zhu, Bolin Liao
Summary: By using in situ laser illumination inside a scanning electron microscope, this study characterizes the photo-induced ion migration in perovskites. Long-range migration of halide ions both on the surface and inside the bulk, as well as the vertical migration of lead ions, were observed. These findings provide valuable insights for the design and processing of perovskite materials.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Yang Gao, Qiming Sun, Jason M. Yu, Mario Motta, James McClain, Alec F. White, Austin J. Minnich, Garnet Kin-Lic Chan
Article
Materials Science, Multidisciplinary
Peishi Cheng, Nina Shulumba, Austin J. Minnich
Article
Materials Science, Multidisciplinary
Chengyun Hua, Lucas Lindsay, Xiangwen Chen, Austin J. Minnich
Article
Quantum Science & Technology
Shi-Ning Sun, Mario Motta, Ruslan N. Tazhigulov, Adrian T. K. Tan, Garnet Kin-Lic Chan, Austin J. Minnich
Summary: Employing the quantum imaginary time evolution (QITE) algorithm on five-qubit IBM Quantum devices, we have successfully calculated finite-temperature properties of spin systems with up to four sites, including energy, correlation functions, and excitation spectra. Our work demonstrates that the ansatz-independent QITE algorithm is capable of computing diverse finite-temperature observables on near-term quantum devices, thanks to algorithmic improvements such as exploiting symmetries, circuit optimization, and error-mitigation techniques.