Article
Chemistry, Physical
Daniele Coslovich, Robert L. Jack, Joris Paret
Summary: This study uses unsupervised learning methods to characterize the disordered microscopic structure of supercooled liquids and glasses. Dimensionality reduction is performed on smooth structural descriptors, and the ability of the method to capture the essential structural features of glassy binary mixtures is assessed. The results indicate that some mixtures have well-defined locally favored structures and are reflected in bimodal distributions of structural variables identified through dimensionality reduction.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Alejandro R. Verde, Laureano M. Alarcon, Sebastian R. Accordino, Gustavo A. Appignanesi
Summary: When liquid becomes glass, it undergoes a significant slowdown, but the resulting amorphous solid structure is similar to the liquid state. The supercooled liquid is dynamically heterogeneous, with varying dynamics in different regions. This study focuses on the link between structure and dynamics in supercooled water, showing that regions with structural defects persist during relaxation and can predict glassy relaxation events.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Rinske M. Alkemade, Frank Smallenburg, Laura Filion
Summary: This study explores whether a simple linear regression algorithm combined with intelligently chosen structural order parameters can achieve the accuracy of the current advanced machine learning approaches for predicting dynamic propensity. The research finds that the structure of the cage state is highly predictive of the long-time dynamics of the system compared to the initial and inherent states. By combining the cage state information with the initial state, dynamic propensities can be predicted with unprecedented accuracy over a broad range of time scales, including the caging regime.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Physical
Giulio Biroli, Jean-Philippe Bouchaud, Francois Ladieu
Summary: The anomalous growth of the peak value of nonlinear susceptibilities is a signature of growing amorphous order in glassy systems, with spin-glasses as an example. Experimental results on supercooled liquids support the prediction of compact glassites increasing in volume with decreasing temperature or as the system ages, as explained within the random first-order transition (RFOT). The difficulty in explaining this behavior within purely kinetic theories of glass formation is clarified, despite recent claims to the contrary.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Polymer Science
Valeriy V. Ginzburg
Summary: Understanding the glass transition and glassy dynamics in random copolymers and miscible polymer blends is crucial for fundamental and applied polymer science. The expanded TS2 mean-field model provides a new equation for the characteristic transition temperature, T*, which serves as an approximate predictor for the glass transition temperature Tg. The model allows for refinement of predictions and calculation of relaxation times, showing good qualitative and semi-quantitative agreement with published literature data.
Article
Chemistry, Physical
A. Mansuri, P. Muenzner, T. Feuerbach, A. W. P. Vermeer, W. Hoheisel, R. Boehmer, M. Thommes, C. Gainaru
Summary: This study investigates the molecular dynamics of imidacloprid using dielectric spectroscopy, oscillatory shear rheology, and calorimetry, revealing that the molecular dynamics in its glassy state strongly depends on its thermal history. The research shows that different methods predict different relaxation times, indicating the complexity of imidacloprid's behavior in technological applications.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
John Camkiran, Fabian Parsch, Glenn D. Hibbard
Summary: This study introduces a new measure E to quantify the degree of order surrounding particles. By capturing the pairwise informational redundancy among particle bonds, E can distinguish different structures and possesses intuitive mathematical properties. The findings of this study are generally consistent with existing knowledge and E is shown to be simpler yet more informative compared to existing methods.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Hayato Shiba, Masatoshi Hanai, Toyotaro Suzumura, Takashi Shimokawabe, Takashi Shimokawabe
Summary: Recent developments in machine learning have made accurate predictions of the dynamics of slow structural relaxation in glass-forming systems possible. However, existing machine-learning models mainly focus on learning a single dynamic quantity and its relation to the structural features of glassy liquids. In this study, a graph neural network model called "BOnd TArgeting Network (BOTAN)" is proposed, which learns the relative motion between neighboring pairs of particles and the self-motion of particles. By relating the structural features to these two different dynamical variables, the model can autonomously discern the effects of different dynamical processes on the self-motion of particles undergoing slow relaxation, thus enabling high-precision prediction of slow structural relaxation in space and time.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Yuichiro Tokoro, Tetsuya Nakagawa, Shin-ichi Yamamoto, Toshio Koizumi, Toshiyuki Oyama
Summary: The local ordering of particles in glass transition is considered important but difficult to observe experimentally at the molecular level. In this study, a glass-forming fluorophore was used to reveal changes in intermolecular arrangement and orientation through color changes in photoluminescence spectra. The results showed that the orientation in glass differs from that during crystal growth, suggesting that anisotropic interactions are valuable for uncovering molecular-level events in the glassy state.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Rinske M. Alkemade, Emanuele Boattini, Laura Filion, Frank Smallenburg
Summary: In this study, three different machine learning algorithms were used to predict the dynamic properties of glassy materials. The results show that all three methods achieve similar accuracy when advanced structural descriptors are used. However, linear regression is significantly faster to train compared to the other methods.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Thomas C. Merlette, Jeirome Hem, Caroline Crauste-Thibierge, Sergio Ciliberto, Florence Clement, Paul Sotta, Didier R. R. Long
Summary: This study proposes an extension to the theory of glassy polymer deformation, taking into account the heterogeneous nature of dynamics and strain-hardening regime. It attributes strain-hardening to the increase of free-energy barriers due to local orientation of monomers. The variation of the local free-energy barriers is given by an expression involving stress, order parameter, and bulk glassy modulus. The contributions of stress and local orientation in strain hardening are discussed.
Article
Multidisciplinary Sciences
Paulina Jesionek, Dawid Heczko, Barbara Hachula, Kamil Kaminski, Ewa Kaminska
Summary: In this paper, the molecular dynamics of hydrogen-bonded active pharmaceutical ingredient-ticagrelor (TICA) under different thermodynamic conditions were investigated. The study revealed that the structural relaxation of TICA is highly sensitive to compression and the shape of the alpha-peak remains unchanged at various temperature and pressure conditions. The hydrogen-bonding pattern in TICA was found to be unaffected by the experimental conditions. High-pressure dielectric measurements also showed the high sensitivity of the slow secondary relaxation to pressure and the isochronal superpositioning of alpha- and JG-beta-relaxation times.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Physical
Till Boehmer, Jan Philipp Gabriel, Rolf Zeissler, Timo Richter, Thomas Blochowicz
Summary: By using depolarized light scattering, the study investigates a series of polyalcohols and finds that the structural relaxation behavior varies significantly due to different microscopic mechanisms. Short-chained polyalcohols rotate as rigid entities, while long-chained polyalcohols show intramolecular dynamic contributions to structural relaxation.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Ceramics
Chih-Yu Lee, Chuanyu Lian, Hongyi Sun, Yi-Siou Huang, Niloy Acharjee, Ichiro Takeuchi, Carlos A. Rios Ocampo
Summary: Chalcogenide phase change materials (PCMs) offer great potential for the Optics and Photonics community, providing nonvolatility and large optical property modulation for devices with low-energy consumption and ultra-compact form factors. Precisely controlling the glassy amorphous and crystalline domains of PCMs is a challenging task, but essential for achieving intermediate optical response and repeatable reconfiguration.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Polymer Science
Heewoon Shin, Jowon Shin, Ryan C. Hayward, Hyeong Jun Kim
Summary: Ionoelastomers, consisting of cross-linked networks of polymerized ionic liquids, have unique electrochemical properties. This study investigates the structure of the electric double layer (EDL) at electrified surfaces of IEs and finds that the capacitance of fixed ions is lower than that of counterions in both polyanion and polycation IEs, resulting in an asymmetric capacitance response depending on the applied voltage. The elastic energy of the cross-linked networks restricts the rearrangement of polymeric ions at the electrified surfaces, thereby reducing the EDL capacitance.
Article
Multidisciplinary Sciences
Seung Gyo Jeong, Jiwoong Kim, Ambrose Seo, Sungkyun Park, Hu Young Jeong, Young-Min Kim, Valeria Lauter, Takeshi Egami, Jung Hoon Han, Woo Seok Choi
Summary: Chiral symmetry breaking of phonons plays a crucial role in emergent quantum phenomena due to its strong coupling to spin degree of freedom. In this study, a chiral phonon-mediated interlayer exchange interaction was reported in atomically controlled ferromagnetic metal-nonmagnetic insulator heterostructures, resulting in spin rotation and a spin spiral state. The existence of chiral phonons and their interplay with spins in magnetic materials were confirmed through the phonon Zeeman effect and atomic-scale heterostructure approach.
Article
Physics, Multidisciplinary
Hui Wang, Wojciech Dmowski, Yang Tong, Zengquan Wang, Yoshihiko Yokoyama, Jittisa Ketkaew, Jan Schroers, Takeshi Egami
Summary: This study suggests that the plasticity of metallic glasses is related to the local atomic rearrangements under stress, rather than their atomic structure directly. By conducting experiments on various bulk metallic glasses, researchers found that the extent of local deviation from affine deformation within the elastic regime is strongly correlated with the plastic behavior of metallic glasses beyond yield.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Konstantin A. Lokshin, Daniel Mitchell, Maxim Lobanov, Viktor Struzhkin, Takeshi Egami
Summary: This study presents a synthesis method of pure low valence nickelates using a custom built H-2 circulation apparatus. Pure infinite layer LnNiO(2) and La3Ni2O6 nickelates were successfully prepared and characterized. The resistivity of La3Ni2O6 was measured under different temperature and pressure conditions, revealing significant pressure-induced changes in both magnitude and pressure dependence of resistivity. It is proposed that a hidden insulator-metal transition exists in La3Ni2O6 at pressures above 100 GPa.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Leo Zella, Jaeyun Moon, David Keffer, Takeshi Egami
Summary: Metallic glasses exhibit fast mechanical relaxations known as nearly constant loss (NCL) at temperatures below the glass transition. Through molecular dynamics simulations, it is found that NCL relaxation is due to transient groups of atoms that revert to typical atomic-level viscoelastic behavior. These groups of atoms are homogeneously distributed throughout the glass, without any outstanding features.
Article
Chemistry, Physical
Yuya Shinohara, Alexander S. Ivanov, Dmitry Maltsev, Garrett E. Granroth, Douglas L. Abernathy, Sheng Dai, Takeshi Egami
Summary: This study provides experimental insights into the dynamics of molten magnesium chloride at high temperatures, revealing the distance-dependent dynamics of molten salts. The results significantly improve our understanding of the interplay between microscopic structural parameters and dynamics, which ultimately control the physical properties of condensed matter in extreme environments.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Yuya Doi, Juergen Allgaier, Reiner Zorn, Stephan Foerster, Takeshi Egami, Michael Ohl
Summary: In this study, the correlation between polymer dynamics and ionic conductivity in P(EC/EO)-based solid polymer electrolytes (SPEs) at different lithium salt weight fractions (wLi) was investigated through experimental and molecular simulations. The results showed that the molecular motions of P(EC/EO) at various scales changed differently with the addition of lithium salt. Molecular simulations revealed that lithium ions are more likely to coordinate with EC units than EO units in P(EC/EO).
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Andrew S. Westover, Mordechai Kornbluth, Takeshi Egami, Jue Liu, Sergiy Kalnaus, Dong Ma, Andrew K. Kercher, Joerg C. Neuefeind, Michelle Everett, Victor Torres, Steve W. Martin, Boris Kozinsky, Nancy J. Dudney
Summary: In this study, the structure of amorphous ionic glasses LiPON and LiSiPON with high Li content was characterized. The materials were found to have an inverted structure with isolated polyanion tetrahedra or polyanion dimers in a Li+ matrix, as observed through ab initio molecular dynamics simulations. The inverted structure resulted in significant medium-range ordering, indicated by sharp diffraction peaks and periodic structural oscillation. Additionally, the addition of Si increased disorder in the polyanion substructure but enhanced ordering in the O substructure, resulting in a glassy material that is mechanically stiff and ductile on the nanoscale.
CHEMISTRY OF MATERIALS
(2023)
Article
Physics, Condensed Matter
Takeshi Egami, Chae Woo Ryu
Summary: The structure beyond the nearest neighbor atoms in liquid and glass is characterized by the medium-range order (MRO). The conventional approach attributes MRO directly to the short-range order (SRO) of the nearest neighbors. However, a top-down approach is proposed in addition to the bottom-up approach, where global collective forces drive liquid to form density waves. This dual framework provides a novel perspective for describing the structure and dynamics of liquid and glass.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Materials Science, Multidisciplinary
Takeshi Egami, Wojciech Dmowski, Chae Woo Ryu
Summary: In crystals, lattice defects, such as dislocations, control mechanical deformation. Similarly, it is widely believed that even in glasses and liquids some kinds of defects, strongly disordered regions, play a major role in deformation. Recent results raise questions about the assumption that short-range order (SRO) in the nearest-neighbor cage of atoms determines defects in glasses and liquids.
Article
Biochemistry & Molecular Biology
Dima Bolmatov, C. Patrick Collier, Dmitry Zav'yalov, Takeshi Egami, John Katsaras
Summary: This study developed a method to visualize the collective headgroup dipole motions in phospholipid bilayers using 1D, 2D, and 3D Van Hove correlation functions. The study found that the headgroup dipoles exhibit transient collective dynamics at picosecond time scales, transmitting and dissipating heat at longer times through relaxation processes. In addition, the headgroup dipoles generate membrane surface undulations and undergo stretching and squeezing elastic deformations at nanometer length and nanosecond time scales. These intrinsic motions of the headgroup dipoles can be externally stimulated at the GHz-frequency scale, enhancing their flexoelectric and piezoelectric capabilities.
Article
Physics, Multidisciplinary
Jie Dong, Hailong Peng, Hui Wang, Yang Tong, Yutian Wang, Wojciech Dmowski, Takeshi Egami, Baoan Sun, Weihua Wang, Haiyang Bai
Summary: The atomic-scale structural rearrangement of glasses under stress is important for understanding their macroscopic mechanical properties. However, it is challenging to experimentally resolve the atomic-scale structural changes of a deformed glass due to its disordered nature. This study shows that structural anisotropy is correlated with non-affine atomic displacements in glasses, providing an approach to identify atomic-scale non-affine deformation. The study also reveals the atomic-level mechanism responsible for plastic flow, which differs between metallic glasses and covalent glasses.
Article
Physics, Applied
Takeshi Egami
Summary: The discovery of high-temperature superconductivity in cuprates has been a significant breakthrough in superconductivity research, reshaping our understanding of solid-state hybrid systems and opening up new avenues for studying strongly correlated electron systems.
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Takeshi Egami, Chae Woo Ryu
Summary: The atomic pair-distribution function of simple liquid and glass exhibits exponential decay beyond the first peak, representing the medium-range order (MRO). The structural coherence length increases with decreasing temperature and freezes at the glass transition. The conventional bottom-up approach based on short-range order (SRO) fails to explain the strong drive to form MRO, which is different in nature. We propose an alternative top-down approach based on the density wave theory, which provides a more intuitive explanation of the structure of simple liquid and glass by considering the competition and compromise between the local bottom-up and global top-down driving forces.
Article
Physics, Multidisciplinary
Eva Zarkadoula, Yuya Shinohara, Takeshi Egami
Summary: Split-pulse x-ray photon correlation spectroscopy is a promising tool to probe atomic dynamics in liquid and soft-matter, but the heating effect of the x-ray beam poses a major challenge. In this study, molecular dynamics and the two-temperature model are used to investigate the atomic level response of water to x-ray laser pulse. The results show that besides the beam energy, the time delay between the two pulses is also critical for obtaining reliable information on the atomic dynamics of water.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Fluids & Plasmas
Takeshi Egami, Chae Woo Ryu
Summary: This article examines the relationship between medium-range order (MRO) and temperature in liquids and glasses, finding that the structural coherence length of MRO follows the Curie-Weiss law with a negative Curie temperature. The study also suggests that glass transition is induced by the freezing of MRO rather than the nearest-neighbor shell. These findings have important implications for understanding the behavior of liquids and glasses.
