Article
Chemistry, Multidisciplinary
Tianyu Liu, Noah P. Holzapfel, Patrick M. Woodward
Summary: A symmetry mode analysis was performed on hybrid organic-inorganic layered perovskites adopting the n = 1 Ruddlesden-Popper (RP) structure, resulting in 47 symmetrically distinct patterns of octahedral tilting. The crystal structures of compounds in this family were compared with the predictions of the analysis. The majority of the unique structures exhibited symmetries in agreement with octahedral tilting alone, while some compounds showed additional features that further lowered the symmetry.
Article
Chemistry, Physical
Yuji Ikeda, Konstantin Gubaev, Jorg Neugebauer, Blazej Grabowski, Fritz Kormann
Summary: Recent experiments have shown that the chemical composition of body-centered cubic (bcc) refractory high entropy alloys (HEAs) can be adjusted to enhance transformation-induced plasticity (TRIP), leading to improved ductility. A method utilizing symmetry analysis and ab initio calculations has been developed to identify the impact of local lattice distortions on the phase stability of HEAs.
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Physics, Multidisciplinary
Ivo de Medeiros Varzielas, Diogo Ivo
Summary: We study the minimization of multi-Higgs models with broken symmetries. Using the method of geometric minimization, we can analytically minimize the potentials of multi-Higgs models with large symmetries. However, when these symmetries are softly broken, we need to adapt the method. We propose a generalization that considers the effect of soft-breaking terms on the quadratic part of the potential by applying the procedure to restricted orbit spaces. We illustrate our methodology by finding and classifying the minima for an S4 multi-Higgs model with specific softly broken terms.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Applied
L. Zhang, Y. Jiang, D. Smirnov, Z. Jiang
Summary: Broken symmetry and tilting effects are crucial in Weyl semimetals, impacting electronic and optical properties. A realistic four-band model was used to study Landau quantization and magneto-absorption spectrum, revealing that broken symmetry can lead to band reconstruction. This work provides a more realistic understanding of Weyl semimetals' magnetic field response.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Astronomy & Astrophysics
N. Chamoun, C. Hamzaoui, E. Lashin, S. Nasri, M. Toharia
Summary: Inspired by neutrino oscillations data, this study considers implementing exact mu-tau symmetry at the level of the neutrino mass matrix, and deviates from symmetry by adjusting phases to study and describe neutrino phenomenology. The breaking of phases leads to interesting lower bounds on the allowed mass of the lightest neutrino, depending on the ordering of neutrino masses and the CP violating phase. The parameter space for the effective Majorana neutrino mass is also shown to be nontrivially constrained.
Article
Optics
Alexander Poshakinskiy, Ivan Iorsh, Alexander Poddubny
Summary: In this theoretical study, we investigated the interaction between two vibrating quantum emitters and propagating photons near a one-dimensional waveguide. We found that strong optomechanical interaction can lead to the formation of spatially localized multiphonon modes, exhibiting parity-time (PT) symmetry breaking. These localized multiphonon states were interpreted by analyzing the energy spectrum in the quasiclassical approximation.
Article
Multidisciplinary Sciences
Lili Huang, Xin Zhang, Hongyan Zang, Tengfei Lei, Haiyan Fu
Summary: A new 3D offset-boostable symmetric system is proposed by introducing an absolute value function. The system is more fragile and prone to a state of broken symmetry. Coexisting attractor pairs get closer and finally merge together. The basins of attraction demonstrate the arrangement of these coexisting attractors in phase space.
Article
Physics, Applied
Manasi Mandal, Chandan Patra, Anshu Kataria, Suvodeep Paul, Surajit Saha, R. P. Singh
Summary: This work presents the discovery of superconductivity in Ir-doped Weyl semimetal T-d-MoTe2 with broken inversion symmetry. The observation of chiral anomaly induced planar Hall effect and anisotropic magneto-resistance confirms the topological semimetallic nature of Mo1-xIrxTe2. The weak anisotropic, moderately coupled type-II superconductivity observed in T-d-Mo1-xIrxTe2 makes it a promising candidate for topological superconductor.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Minhao He, Jiaqi Cai, Ya-Hui Zhang, Yang Liu, Yuhao Li, Takashi Taniguchi, Kenji Watanabe, David H. Cobden, Matthew Yankowitz, Xiaodong Xu
Summary: Twisted double bilayer graphene has been studied as a platform for studying strongly correlated and topological states. In this research, a phase diagram representing these states as a function of parameters was constructed based on measurements of several devices. Symmetry-broken states were observed at a specific twist angle, including a Chern insulator state with band filling of 7/2 and an incipient state with filling of 11/3. An anomalous Hall effect was also observed at zero magnetic field in samples supporting the symmetry-broken states.
Article
Multidisciplinary Sciences
Li Quan, Simon Yves, Yugui Peng, Hussein Esfahlani, Andrea Alu
Summary: Willis coupling in acoustics, which involves coupling between pressure and particle velocity, can be utilized for controlling and manipulating sound scattering through geometrically asymmetric structures.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Matteo Rossi, Motoki Osada, Jaewon Choi, Stefano Agrestini, Daniel Jost, Yonghun Lee, Haiyu Lu, Bai Yang Wang, Kyuho Lee, Abhishek Nag, Yi-De Chuang, Cheng-Tai Kuo, Sang-Jun Lee, Brian Moritz, Thomas P. Devereaux, Zhi-Xun Shen, Jun-Sik Lee, Ke-Jin Zhou, Harold Y. Hwang, Wei-Sheng Lee
Summary: A charge ordering state has been observed in nickelate superconductors, which is distinct from other observed ordered states. The results suggest that strong electronic correlations may be responsible for this ordered state, and the interplay between charge order, antiferromagnetic fluctuations, and superconductivity is an important topic in nickel-based superconductors.
Article
Physics, Particles & Fields
Ivo de Medeiros Varzielas, Igor P. Ivanov, Miguel Levy
Summary: New methods are developed to study the scalar sector of multi-Higgs models with large discrete symmetry groups that are softly broken. Soft breaking terms are identified to play different roles in preserving or shifting the symmetric vacuum expectation value alignment, with some structural features inherited from the parent symmetric model and persisting even without exact symmetry. The general procedure is illustrated with the example of the three-Higgs-doublet model with the softly broken symmetry group Sigma(36).
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Biology
David C. Krakauer
Summary: Complex phenomena arise when fundamental physical symmetries are broken and selected ground states from the set of broken symmetries are utilized for mechanical work and adaptive information storage. Philip Anderson identified key principles that can result from symmetry breaking in complex systems, including emergence, frustrated random functions, autonomy, and generalized rigidity. These principles, collectively known as the four Anderson Principles, are prerequisites for the emergence of evolved function. This article summarizes these ideas and briefly discusses recent extensions related to functional symmetry breaking, encompassing information, computation, and causality.
Article
Nanoscience & Nanotechnology
Nayoung Kim, Myungjoon Kim, Joonkyo Jung, Taeyong Chang, Suwan Jeon, Jonghwa Shin
Summary: Optical metasurfaces show potential to overcome limitations in conventional optical devices. This paper focuses on angle-multiplexed metasurfaces and proposes optimized designs using effective medium theory and breaking mirror symmetry to achieve high sensitivity and efficiency. Two applications, an angle-multiplexed beam-steering device and an angle-multiplexed metalens array, are highlighted for their potential in LiDAR, augmented reality glasses, and imaging.
Article
Optics
Yang Gao, Bin Ge
Summary: In this study, the second harmonic generation in tilted Dirac/Weyl semimetals was theoretically investigated using quantum theory, deriving an analytical formula for the second harmonic conductivity tensor. The conductivity showed contributions from both intraband and interband-intraband transitions at different frequency regions. Additionally, the high-frequency region exhibited resonant peaks in the nonlinear conductance due to the two-photon absorption process, revealing a high nonlinear susceptibility in Dirac/Weyl semimetals.
Article
Physics, Multidisciplinary
Songbin Cui, Tae-Hwan Kim, Ungdon Ham
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2020)
Article
Physics, Multidisciplinary
Songbin Cui, Tae-Hwan Kim, Ungdon Ham
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2020)
Article
Multidisciplinary Sciences
Chang-geun Oh, Sang-Hoon Han, Seung-Gyo Jeong, Tae-Hwan Kim, Sangmo Cheon
Summary: Novel properties of topological chiral solitons, such as PA duality and fractional charge e/2, have been demonstrated, leading to support for topological Z4 algebraic structures and inspirations for research on feasible and promising topological systems.
SCIENTIFIC REPORTS
(2021)
Article
Multidisciplinary Sciences
Sungyu Park, So Young Kim, Hyoung Kug Kim, Min Jeong Kim, Taeho Kim, Hoon Kim, Gyu Seung Choi, C. J. Won, Sooran Kim, Kyoo Kim, Evgeny F. Talantsev, Kenji Watanabe, Takashi Taniguchi, Sang-Wook Cheong, B. J. Kim, H. W. Yeom, Jonghwan Kim, Tae-Hwan Kim, Jun Sung Kim
Summary: Superconductivity often arises from the suppression of competing electronic orders. In this case, the authors present a contrary example showing a superconducting dome within the parent phase with a stripe charge order in IrTe2 nanoflakes, highlighting their unusual superconducting properties.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Sun-Woo Kim, Hyun-Jung Kim, Sangmo Cheon, Tae-Hwan Kim
Summary: This study investigates the interaction between circularly polarized light and emergent chiral stacking orders in quasi-one-dimensional charge density waves. Using density functional theory calculations, the researchers find that left- and right-chiral stacking orders exhibit distinct circular dichroism responses, while nonchiral stacking orders do not show circular dichroism.
PHYSICAL REVIEW LETTERS
(2022)
Letter
Materials Science, Multidisciplinary
Seung-Gyo Jeong, Tae-Hwan Kim
NPJ QUANTUM MATERIALS
(2022)
Article
Physics, Multidisciplinary
Hyoung Kug Kim, Dowook Kim, Dong Guk Lee, Eun-Su Ahn, Hyeon-Woo Jeong, Gil-Ho Lee, Jun Sung Kim, Tae-Hwan Kim
Summary: Quasi-two-dimensional (Quasi-2D) van der Waals (vdW) materials can be mechanically or chemically exfoliated down to monolayer, exhibiting thickness-dependent electronic properties. Surface-sensitive scanning tunneling microscopy (STM) can provide direct observation of such materials, but maintaining their intrinsic surfaces between preparation and measurement is challenging. In this study, a method that preserves air-sensitive quasi-2D vdW materials and allows access to specific thicknesses using STM navigation is presented. The method involves exfoliating and transferring the materials in a glove box, and locating the exfoliated flakes with different thicknesses on the surface. This experimental improvement provides a new way to investigate air-sensitive layered vdW materials with various thicknesses via surface-sensitive techniques.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Physics, Multidisciplinary
Wooin Yang, Dowook Kim, Hyoung Kug Kim, Tae-Hwan Kim
Summary: We use scanning tunneling microscopy to investigate mechanically exfoliated thin 1T-TaS2 at room temperature. Sample preparation without air exposure allows us to study the intrinsic charge-density-wave (CDW) phases of thin 1T-TaS2. At room temperature, we observe the nearly commensurate CDW (NCCDW) phase on thin flakes, similar to bulk 1T-TaS2. Further analysis reveals that the CDW domains in the NCCDW phase become smaller and have a more anisotropic shape with decreasing thickness in the range of 8-28 layers.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Physics, Multidisciplinary
Wooin Yang, Dowook Kim, Hyoung Kug Kim, Tae-Hwan Kim
Summary: Lower thermal stability in thinning low-dimensional materials often gives rise to unprecedented hidden phases, which can coexist or compete with preexisting electronic phases. In this study, we investigate the hidden phases observed in atomically thin 1T-TaS2 and find a hidden stripe phase that can be electrically induced and coexists with a nearly commensurate charge-density-wave phase. We also observe the spontaneous appearance of the emergent stripe phase without any electric excitation on a tiny flake. These findings provide a potential explanation for previously observed phase transitions and optical responses in thin 1T-TaS2 devices at room temperature, and shed light on exotic CDW-related phenomena in 1T-TaS2.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Instruments & Instrumentation
Taemin Ahn, Sungmin Song, Ungdon Ham, Tae-Hwan Kim
Summary: Piezoelectric motors are commonly used in applications requiring precision positioning and miniaturization. Wear-induced cold welding is a common issue in long-term use, especially in vacuum environments. In this study, we investigated the practical reliability of various UHV-compatible lubricant coatings and found that polytetrafluoroethylene (PTFE) coating showed the most reliable long-term operation in vacuum, while other coatings eventually led to motor failure. Coating the slider surface with PTFE provides a simple and effective way to improve the long-term performance of UHV piezoelectric motors.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Physics, Applied
Tae Soo Kim, Taemin Ahn, Tae-Hwan Kim, Hee Cheul Choi, Han Woong Yeom
Summary: Recent research shows that atomic oxygen can oxidize epitaxial graphene in a vacuum without causing damage. In this study, the effects of chemisorbed atomic oxygen on the electronic properties of graphene were investigated using scanning tunneling microscopy (STM). The results reveal that oxygen atoms can modify the electronic states of graphene, creating a bandgap at its Dirac point. Additionally, it was demonstrated that selective desorption or hopping of oxygen atoms can be induced with atomic precision using appropriate bias sweeps with an STM tip. These findings suggest the potential for atomic-scale tailoring of graphene oxide and the development of graphene-based atomic-scale electronic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Seung-Gyo Jeong, Sang-Hoon Han, Tae-Hwan Kim, Sangmo Cheon
Summary: In this study, the authors investigate hidden chiral domain wall states and their topological properties in a double-chain Su-Schrieffer-Heeger model and elucidate a series of single and double gap phases that occur by varying the dimerization and interchain coupling.
COMMUNICATIONS PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Hyoung Kug Kim, So Young Kim, C. J. Won, Sang-Wook Cheong, Jonghwan Kim, Jun Sung Kim, Tae-Hwan Kim
Summary: In this study, the dimensional crossover of charge order in IrTe2 from genuine two- to quasi-three-dimensions was observed using low-temperature scanning tunneling microscopy and spectroscopy. It was found that the charge order undergoes a gradual phase transition and the Coulomb gap decays exponentially with increasing thickness. Additionally, a suppression of the density of states was observed at the abrupt lateral interface between two and three dimensions. These findings provide new insights into the dimensional crossover of strongly coupled layered materials with hidden electronic phases.
Article
Nanoscience & Nanotechnology
Songbin Cui, Tae-Hwan Kim, Ungdon Ham
Summary: Research has found that asymmetric nano-tip shapes can result in different STL spectra in different directions, providing an effective way to characterize the optical properties of nanomaterials by tuning the STL spectra.
ACS APPLIED NANO MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Sun-Woo Kim, Hyun-Jung Kim, Sangmo Cheon, Tae-Hwan Kim