Article
Nanoscience & Nanotechnology
Xiaolin Chen, Hongfei Wang, Jensen Li, Kwok-yin Wong, Dangyuan Lei
Summary: In this study, the scattering properties of coupled parity-time (PT) symmetric chiral nanospheres were investigated using a scattering matrix formalism. The results showed that the scattering cross section exhibited asymmetry under different incident light environments, while the optical cross section displayed circular dichroism, especially when the PT-symmetric scatter possessed chirality. Additionally, gain and loss were found to control optical chirality, enhancing chiroptical interactions and paving the way for studying resonant chiral light-matter interactions in non-Hermitian photonics.
Article
Optics
Peng Guo, Vladimir Gasparian, Esther Jodar, Christopher Wisehart
Summary: In this study, we propose a generalized approach to tunneling time in parity and time (PT)-symmetric systems. The properties of tunneling time in PT-symmetric systems are examined using a simple contact interaction periodic finite-size diatomic PT-symmetric model. The physical interpretation of negative tunneling time in PT-symmetric systems and its relationship to spectral singularities are discussed.
Article
Nanoscience & Nanotechnology
Zhicheng Xiao, Andrea Alu
Summary: The study explores a hybrid parity-time and anti-parity-time symmetric system that supports highly tunable Fano resonances. This system can be implemented in nanophotonic and microwave circuits for real-time control of scattering line shapes, demonstrating the opportunities enabled by non-Hermitian platforms in controlling scattering line shapes for various photonic, electronic, and quantum systems. The potential applications include high-resolution imaging, switching, sensing, and multiplexing.
Article
Physics, Applied
Xiaolin Chen, Yiqi Chu, Kai Chen, Kai Zhang, Xian Wang, Qiaoxia Luo, Yong Zhou, Xiaohui Ma, Wentan Fang, Wei Zhang, Song Huang, Weiqing Gao
Summary: We investigate the chiral spectral singularities, known as laser threshold modes, in PT-symmetric dielectric metasurfaces produced through quasi-bound states in the continuum. By increasing balanced gain and loss, the poles, referred to as the quasi-bound states in the continuum, of the scattering matrix can transition from the lower half-plane to the upper complex frequency plane. Theoretical demonstration of the maximal intrinsic optical chirality of the laser threshold mode is achieved through large transmission circular dichroism spectra. Our work lays the foundation for studying enhanced optical chirality in non-Hermitian nanophotonics enabled by quasi-bound states in the continuum, along with various intriguing applications such as chiral coherent perfect absorber and laser.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Ankit Negi, Hwang Pill Kim, Zilong Hua, Anastasia Timofeeva, Xuanyi Zhang, Yong Zhu, Kara Peters, Divine Kumah, Xiaoning Jiang, Jun Liu
Summary: This paper demonstrates the room-temperature thermal modulation in 2.5 mm-thick Pb(Mg1/3Nb2/3)O-3-xPbTiO(3) (PMN-xPT) single crystals. Through the use of advanced poling conditions and a systematic study on composition and orientation dependence, a range of thermal conductivity switching ratios, with a maximum of approximately 1.27, is observed. The simultaneous measurements of piezoelectric coefficient (d(33)), domain wall density using polarized light microscopy (PLM), and birefringence change using quantitative PLM reveal an increase in domain wall density at intermediate poling states (0< d(33)< d(33(max)) compared to the unpoled state.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Cynthia P. Quinteros, Maria Jose Cortes Burgos, Lucas J. Albornoz, Javier E. Gomez, Pablo Granell, Federico Golmar, Maria Lujan Ibarra, Sebastian Bustingorry, Javier Curiale, Mara Granada
Summary: This study investigates the effects of different growth conditions, such as Co thickness, substrate roughness, and deposition chamber base pressure, on domain wall motion in the Pt/Co/Pt system. It was found that Co thickness has a significant impact on coercive field and domain wall velocity, while substrate roughness and base pressure selectively affect domain wall nucleation and propagation, providing a tool to tune these properties.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Fuping Zhang, Weikang Liu, Li Chen, Zhiqiang Guan, Hongxing Xu
Summary: A plasmonic waveguide is crucial for high-speed optical communication and sensing, with gold nanostrips on a silicon-on-insulator wafer proposed as an effective solution. Controlled fabrication processes allow for improved scattering intensity and potential integration in compact plasmonic devices.
Article
Optics
S. M. Zhang, H. S. Xu, L. Jin
Summary: In this study, we introduce an anti-parity-time symmetric imaginary coupling in a generalized Creutz ladder to construct a non-Hermitian AB cage with tunable flat-band energy. We investigate compact localized states and complete localization dynamics, and show that non-Hermiticity affects the localization probability distributions and increases the oscillation period of the AB cage dynamics.
Article
Nanoscience & Nanotechnology
Jeng Yi Lee, Pai-Yen Chen
Summary: With consideration of PT symmetry, Lorentz reciprocity theorem, and real Bloch phase, this work proposes a generalized parametric space to comprehensively illustrate the PT phase transition, Bloch phase, and necessary conditions of exotic wave scattering in finite periodic PT photonic structures. Parametrization is used to derive analytical formulas for the complex relative permittivities of the unit cells composed of subwavelength gain-loss heterostructures, providing a guideline for manipulating different PT scattering events. Several one-dimensional PT photonic systems are studied to achieve exotic wave scattering enabled by PT symmetry. This work offers a theoretical underpinning for studying extraordinary wave phenomena in PT-symmetric photonics and opens avenues for manipulation of light.
Article
Optics
F. A. Shuklin, C. Tserkezis, N. Asger Mortensen, C. Wolff
Summary: This study analyzes the emergence of unphysical superluminal group velocities in Su-Schrieffer-Heeger (SSH) parity-time (PT) symmetric chains and explores the origins of this behavior. The analysis reveals that material dispersion is the key factor causing the divergence of group velocities. Restoring causality resolves the issue and sets practical limits on the performance of PT-symmetric systems.
Article
Optics
Jinal Tapar, Saurabh Kishen, Naresh Kumar Emani
Summary: All-dielectric nanophotonics is a rapidly developing and practical alternative to plasmonics for nanoscale optics. Recently, nanophotonic structures satisfying parity-time (PT) symmetry have been shown to exhibit a novel scattering anomaly called lasing spectral singularity. This paper analyzes the direction-sensitive scattering response of the PT-symmetric GaInP metasurface and explores the design of tunable sources with direction-sensitive emission properties.
Article
Engineering, Electrical & Electronic
Henning Mextorf, Winfried Schernus
Summary: This article presents a novel branch-line coupling topology that outperforms the conventional branch-line coupler. The proposed network structure is simple, requiring only one additional transmission line element to enhance the bandwidth by approximately 25%. The analysis of the proposed structure is based on even-odd analysis, and closed-form expressions for dimensioning the network parameters are provided. The transmission-line impedances are equal or very close to the system's impedance, eliminating the need for very low or high transmission-line impedances.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Mechanics
Mohamin B. M. Khan, Harekrushna Behera, Trilochan Sahoo, S. Neelamani
Summary: This study developed a numerical model using multi-domain boundary element method to investigate the effects of multiple layers in a rubble mound breakwater on the reflection and dissipation of incoming ocean waves. The study examined hydrodynamics in different configurations and highlighted the influence of armour layers on various structural and wave parameters.
Article
Chemistry, Physical
I. Morawski, M. Nowicki
Summary: The multiple scattering formalism is used to describe the scattering events of primary electron beams in crystalline solids, resulting in theoretical distributions of elastically backscattered electrons and Auger electrons. Numerical calculations reveal characteristic intensity maxima and bands associated with crystalline directions and planes. The effects of sample structure, atomic scattering properties, lattice parameters, layer location, and sample chemical composition are discussed. The short range order structural information can be applied in modeling heterostructures and calculating signal distributions.
APPLIED SURFACE SCIENCE
(2022)
Article
Engineering, Mechanical
Yingying Xie, Lingfei Li, Jingyu Wu, Yaoping Wang, Liquan Mei
Summary: This paper derives a family of rational solutions with several non-zero offset parameters for a non-compatible partially PT symmetric Davey-Stewartson system. The obtained solutions consist of a single symmetric soliton or a few independent breathers. Our results not only perfectly retrieve the solutions obtained by the Darboux transformation for the focusing nonlinear Schrodinger equation but also extend it to the version containing free parameters.
NONLINEAR DYNAMICS
(2023)
Article
Physics, Multidisciplinary
Da Ke, Wei Zhong, Sergey Dmitriev, Daxing Xiong
Summary: We have developed an effective numerical scheme to capture hydrodynamic modes in classical anharmonic chains. Our results show the limitations of the current theories and provide new insights into thermal transport.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Optics
Alena Yu Kolesnikova, Sergey Suchkov, Ilya D. Vatnik
Summary: We study the nonlinear mode interaction in a cylindrical microresonator with nanoscale radius variation and demonstrate the generation of broadband stable low-repetition-rate frequency combs based on axial-azimuthal modes.
Article
Acoustics
A. Savin, E. A. Korznikova, S. Dmitriev
Summary: The study investigates the linear and nonlinear dynamic excitations in CNT bundle and reveals the existence of compressive solitons and discrete breathers in the bundle. It also uncovers new channels of energy localization and transport, which are crucial for the use of CNT bundles in various technologies.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Chemistry, Physical
Alina Y. Morkina, Dmitry Bachurin, Sergey Dmitriev, Aleksander S. Semenov, Elena A. Korznikova
Summary: This study investigates the modulation instability of four DNVMs in a single crystal of fcc copper using molecular dynamics methods. The results show that all four DNVMs exhibit a hard-type anharmonicity and lead to the formation of chaotic DBs. Furthermore, the growth of modulation instability results in an increase in mechanical stresses and a decrease in the heat capacity of the crystal.
Article
Materials Science, Multidisciplinary
L. Kh. Galiakhmetova, D. V. Bachurin, E. A. Korznikova, A. M. Bayazitov, A. A. Kudreyko, S. V. Dmitriev
Summary: This study investigates a single-walled carbon nanotube (CNT) bundle under shock loading and finds that the energy absorption rate is affected by the diameter of the CNT bundle, and the rate of energy absorption increases with the piston speed.
MECHANICS OF MATERIALS
(2022)
Article
Chemistry, Physical
Ayrat M. Bayazitov, Dmitry Bachurin, Yuri Bebikhov, Elena A. Korznikova, Sergey Dmitriev
Summary: The mass transfer along an octahedral channel in an fcc copper single crystal is studied using molecular dynamics. The initial position and velocity of the bombarding atom influence its penetration depth and energy dissipation. Deviation from the center of the channel leads to additional velocity components and increased energy dissipation. The findings provide insight into the mechanism of mass transfer during ion implantation and other experimental techniques.
Article
Chemistry, Physical
Igor Kosarev, Sergey Dmitriev, Alexander S. Semenov, Elena A. Korznikova
Summary: This study analyzes the range of stability of planar stanene under uniform in-plane deformation and compares it with graphene. It is found that the thickness of stanene can be changed by tensile strain, while shear strain reduces its stability. Furthermore, the possibility of domain formation separated by domain walls in stanene is predicted.
Article
Engineering, Mechanical
D. S. Ryabov, G. M. Chechin, E. K. Naumov, Yu. V. Bebikhov, E. A. Korznikova, S. V. Dmitriev
Summary: This paper analyzes all possible one-component delocalized nonlinear vibrational modes (DNVMs) in a square lattice. The DNVMs are obtained solely based on the symmetry of the lattice, thus existing regardless of the particle interactions. The interactions between nearest and next nearest neighbors are described using the beta-FPUT potential. Frequency, kinetic and potential energies of each DNVM are described as functions of amplitude. The paper also presents mechanical stresses caused by DNVMs and the effect of DNVMs on the lattice's stiffness constants. DNVMs with higher vibration frequencies have a stronger impact on the lattice's mechanical properties. Analytical analysis of DNVMs is provided. It is discovered that two out of the sixteen one-component DNVMs can have frequencies above the phonon band across their entire amplitude range. These DNVMs can be used to construct discrete breathers by applying localizing functions. The modulational instability of these two DNVMs leads to the formation of chaotic DBs. The presented results contribute to a better understanding of the nonlinear dynamics of a square lattice by analyzing the properties of a class of delocalized exact solutions and demonstrating their connection with discrete breathers.
NONLINEAR DYNAMICS
(2023)
Article
Materials Science, Multidisciplinary
Alina Y. Morkina, Rita I. Babicheva, Elena A. Korznikova, Nariman A. Enikeev, Kaveh Edalati, Sergey V. Dmitriev
Summary: Molecular dynamics simulations were used to study the mechanical dissolution of Zr in Al. The orientation of the grain boundary was found to affect the mixing efficiency of alloy components, with a normal orientation promoting better dissolution of Zr.
Article
Physics, Fluids & Plasmas
Alexander V. Savin, Sergey V. Dmitriev
Summary: The nonlinear dynamics of a one-dimensional molecular crystal composed of a chain of planar coronene molecules was analyzed using molecular dynamics. The study found that the chain of coronene molecules supports acoustic solitons, rotobreathers, and discrete breathers. Increasing the size of planar molecules in the chain leads to an increase in the number of internal degrees of freedom, resulting in a higher rate of phonon emission from spatially localized nonlinear excitations and a shorter lifetime. These findings contribute to the understanding of the impact of rotational and internal vibrational modes on the nonlinear dynamics of molecular crystals.
Article
Physics, Fluids & Plasmas
E. K. Naumov, Yu. V. Bebikhov, E. G. Ekomasov, E. G. Soboleva, S. V. Dmitriev
Summary: By applying localizing functions to the delocalized nonlinear vibrational modes (DNVMs) previously discovered by Ryabov and Chechin, we obtained standing and moving discrete breathers (or intrinsic localized modes) in a square beta-Fermi-Pasta-Ulam-Tsingou lattice. Although the initial conditions used in our study do not correspond to exact spatially localized solutions, they allowed for the realization of long-lived quasibreathers. This approach can also be applied to search for quasibreathers in three-dimensional crystal lattices with DNVMs having frequencies outside the phonon spectrum.
Article
Physics, Condensed Matter
E. K. Naumov, Yu. V. Bebikhov, S. V. Dmitriev
Summary: In recent decades, there has been much interest in nonlinear lattice vibrations, especially in the context of high-amplitude impacts on crystalline materials. This interest arises from the possibility of spatially localized high-amplitude vibrations, known as discrete breathers (DBs) or intrinsic localized modes. While the problem of finding DBs in one-dimensional crystals is relatively simple, general approaches for high-dimension crystal lattices have not been developed. This study aims to analyze and describe DBs in a two-dimensional square lattice using a localizing function, resulting in new types of DBs including one-dimensional and zero-dimensional localizations.
PHYSICS OF THE SOLID STATE
(2023)
Article
Physics, Fluids & Plasmas
D. U. Abdullina, Yu. V. Bebikhov, M. V. Khazimullin, A. A. Kudreyko, S. V. Dmitriev
Summary: This study numerically simulates the interaction between an atomic cluster with a speed v0 and a Frenkel-Kontorova chain. The results show that different scenarios of the molecule-chain interaction can be observed depending on the values of N and v0. The study highlights the formation of supersonic crowdions and the sputtering of atoms from the chain at high collision velocities. Interestingly, the sputtering yield demonstrates a nonmonotonous dependence on v0.
Article
Chemistry, Physical
Leysan Kh Galiakhmetova, Igor S. Pavlov, Ayrat M. Bayazitov, Igor Kosarev, Sergey Dmitriev
Summary: This study presents the first description of two fullerites based on cubenes, one belonging to the cubic system and the other to the triclinic system. The results show that the cubic phase is metastable, while the triclinic phase is likely the ground state crystalline phase. These findings are significant for studying the physical and mechanical properties of C-8 fullerite.
Article
Physics, Fluids & Plasmas
Rita Babicheva, Alexander S. Semenov, Stepan A. Shcherbinin, Elena A. Korznikova, Aleksey A. Kudreyko, Priyanka Vivegananthan, Kun Zhou, Sergey Dmitriev
Summary: This article analyzes the relationship between the properties of one-component delocalized nonlinear vibrational modes (DNVMs) in a face-centered cubic (fcc) lattice and the stiffness of the Morse potential. The study reveals that DNVMs may have frequencies above the phonon band at different stiffness values of interparticle bonds, which is crucial for predicting the possible types of discrete breathers supported by the fcc lattice.
