Article
Physics, Applied
Shengqun Guo, Jinke Huang, Ruimin Huang, Shaojian Su, Zhili Lin, Weibin Qiu
Summary: In this work, three-dimensional pyrochlore topological circuits with a third-order topological corner state were experimentally realized. The corner state, localized on a single corner due to passing through the Wannier center, can exist in the band gap or the continuum due to the generalized chiral symmetry. This work provides a paradigm for exploring various topological phenomena in higher-dimensional systems using topological circuits, which may have potential applications in future communication and signal processing.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Danwei Liao, Zhiwang Zhang, Ying Cheng, Xiaojun Liu
Summary: This study proposes a subwavelength acoustic third-order topological insulator based on the theoretical framework of acoustic transmission lines, which enables the engineering of acoustic negative couplings to achieve topological corner states. The occurrence of these states in both the 3D Su-Schrieffer-Heeger (SSH) model and the octupole insulator is validated through topological invariant calculations and numerical simulations in analogous acoustic networks.
Article
Optics
Xiaoxue Li, Guanghao Rui, Jun He, Bing Gu
Summary: In this study, we successfully constructed third-order topological insulators based on three-dimensional photonic crystals and observed the degeneration behavior of topological states for the first time. This research opens up new directions for the study of topological photonics.
Article
Materials Science, Multidisciplinary
K. M. Fijalkowski, N. Liu, M. Hartl, M. Winnerlein, P. Mandal, A. Coschizza, A. Fothergill, S. Grauer, S. Schreyeck, K. Brunner, M. Greiter, R. Thomale, C. Gould, L. W. Molenkamp
Summary: Recent research on axion electrodynamics has shown that axion insulators must contain a nontrivial volume to host the axion term. Detailed magneto-transport analysis has provided evidence for a quantized topological magneto-electric effect, allowing for the identification of signatures of axion electrodynamics.
Article
Physics, Applied
Jimin Wang, Alexander Kurzendorfer, Lin Chen, Zhiwei Wang, Yoichi Ando, Yang Xu, Ireneusz Miotkowski, Yong P. Chen, Dieter Weiss
Summary: The study found that in a high-quality three-dimensional topological insulator film, carrier density can be independently tuned on top and bottom surfaces using gate electrodes, resulting in different conduction channels with varying mobility and density.
At low temperatures, conduction is dominated by Dirac surface states, leading to only two dominant conduction channels, while at high temperatures, a third channel emerges due to bulk effects, with different mobility and density characteristics.
APPLIED PHYSICS LETTERS
(2021)
Article
Multidisciplinary Sciences
Tianyi Hu, Weiliang Zhong, Tingfeng Zhang, Weihua Wang, Z. F. Wang
Summary: This work experimentally demonstrates the existence of second-order topological corner states in two-dimensional metal-organic frameworks (2D MOFs) with a star-lattice configuration. The unique topological corner state is directly identified in monolayer Ni3(HITP)2.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Ying Wang, Gautam Rai, Stephan Haas, Anuradha Jagannathan
Summary: This study considers a two-dimensional extension of the Su-Schrieffer-Heeger model with a nontrivial topological band structure. The inhomogeneous superconducting phases induced by an attractive -U Hubbard interaction are investigated using mean-field theory. It is shown analytically and numerically that enhanced superconducting order can appear on the corners or edges of lattices with open boundaries, depending on the filling. For finite samples at half filling, the corner site superconducting transition temperature can be significantly higher than that of the bulk. A novel proximity effect is observed in which the corner site creates a nonzero tail of superconducting order in the bulk, which should be observable for a range of r and U values.
Article
Physics, Applied
Lei Liu, Yueke Wang, Mingxing Li, Feixiang Zheng, Haiquan Zhou
Summary: In this study, a zigzag edge-like structure based on C-4 symmetrical lattice was proposed as a lightwaveguide, achieving the CCSW mode through weak coupling. The characteristics of slow light and its robustness compared to other waveguides were discussed.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Multidisciplinary Sciences
Liping Ye, Chunyin Qiu, Meng Xiao, Tianzi Li, Juan Du, Manzhu Ke, Zhengyou Liu
Summary: Dislocations in solid-state materials have a significant impact on wave propagation due to their topological properties. However, the experimental evidence supporting this observation has been lacking. In this study, the researchers used a 3D acoustic weak topological insulator with controllable dislocations to provide direct experimental evidence for the existence of one-dimensional topological dislocation modes.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Hao-Jie Lin, Hai-Peng Sun, Tianyu Liu, Peng-Lu Zhao
Summary: In this study, we investigate the hybridization of boundary states in films of three-dimensional chiral second-order topological insulators (SOTIs) both analytically and numerically. We find that the gaps of two gapped surfaces increase as the film thickness decreases, while the hybridization of chiral edge states can gap the gapless chiral hinge states and destroy the SOTIs. Additionally, we show that the gapless surfaces in a finite-sized system can be gapped due to the hybridization of surface states.
Article
Multidisciplinary Sciences
Gui-Geng Liu, Zhen Gao, Qiang Wang, Xiang Xi, Yuan-Hang Hu, Maoren Wang, Chengqi Liu, Xiao Lin, Longjiang Deng, Shengyuan A. Yang, Peiheng Zhou, Yihao Yang, Yidong Chong, Baile Zhang
Summary: This paper introduces an experimental demonstration of exploring Chern vectors in three-dimensional topological materials. The researchers used magnetically tunable photonic crystals to achieve Chern vectors and their topological surface states. The experimental results demonstrate that Chern vectors are intrinsic bulk topological invariants in three-dimensional topological materials.
Article
Physics, Multidisciplinary
Haoran Xue, Ding Jia, Yong Ge, Yi-jun Guan, Qiang Wang, Shou-qi Yuan, Hong-xiang Sun, Y. D. Chong, Baile Zhang
Summary: The study reveals the helical modes induced by dislocations in three-dimensional topological insulators, and experimentally observes and numerically verifies these modes serving as robust waveguides in three-dimensional media.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Xin Xie, Jianchen Dang, Sai Yan, Weixuan Zhang, Huiming Hao, Shan Xiao, Shushu Shi, Zhanchun Zuo, Haiqiao Ni, Zhichuan Niu, Xiangdong Zhang, Can Wang, Xiulai Xu
Summary: The paper discusses the optimization and robustness of the topological corner state in the second-order topological photonic crystal both theoretically and experimentally, achieving a maximum quality factor of about 6000 and demonstrating robustness against strong disorders. This provides a solid foundation for further investigations and applications of the topological corner state.
Article
Optics
Aoqian Shi, Bei Yan, Rui Ge, Jianlan Xie, Yuchen Peng, Hang Li, Wei E. Sha, Jianjun Liu
Summary: The topological coupled cavity-waveguide (TCCW) based on topological corner state (TCS) and topological edge state (TES) in two-dimensional photonic crystal (PC) offers strong optical localization and high quality factor compared to conventional coupled cavity-waveguide (CCCW). This research is expected to advance the design of high-performance micro-nano integrated photonic devices and expand their applications.
Article
Materials Science, Multidisciplinary
O. J. Franca, Stefan Yoshi Buhmann
Summary: We study how transition radiation is modified by the presence of a generic magnetoelectric medium, with a special focus on topological insulators. We find that the electric field is a superposition of spherical waves and lateral waves, both having a purely topological origin. The main contribution to the radiation in a region far from the interface comes from the spherical waves.
Article
Engineering, Electrical & Electronic
Wei Liu, Jun Chen Ke, Cong Xiao, Lei Zhang, Qiang Cheng, Tie Jun Cui
Summary: A broadband polarization-reconfigurable converter (BPRC) based on active metasurfaces is proposed, which can achieve polarization-reconfigurable conversion for both linear-polarization (LP) and circular-polarization (CP) incident waves in wide bands by changing the states of p-i-n diodes. The BPRC consists of three-layer metal patches, three-layer dielectric substrates, and p-i-n diodes. The conversion ratio is higher than -1 dB in the frequency range of 7.4-12 GHz, with a relative bandwidth of 47.4%.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Optics
Li Zhongfu, Hsun-Chi Chan, ShiXiang Xu, YuanJiang Xiang
Summary: In this study, two pairs of triply degenerate points (TDPs) are proposed in a 3D metamaterial by breaking the time reversal symmetry. Asymmetric surface states with spin-polarization are revealed based on these TDPs, and a topological chiral beam splitter is demonstrated. The study provides a new platform to study spin-polarization surface states and the enhanced spin photonic Hall effect in metamaterials.
Article
Mathematics
Cuixia Li, Zhiquan Shang, Li Shi, Wenlong Gao, Shuyan Zhang
Summary: This paper proposes a novel model named IC-SNN to solve the difficulty of network training in SNN. The model eliminates residual membrane potential and encoding errors, enabling the network to achieve high accuracy in a low number of time steps.
Article
Physics, Applied
Xiao Qing Chen, Lei Zhang, Tie Jun Cui
Summary: A physics-driven vector-quantized intelligent autoencoder model is proposed for fast and accurate generation of optimized discrete STC matrices based on desired harmonic scattering patterns. It enhances the practicality and versatility of STC digital metasurfaces.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Sheng Long, Jie Yang, Hanyu Wang, Zhide Yu, Biao Yang, Qinghua Guo, Yuanjiang Xiang, Lingbo Xia, Shuang Zhang
Summary: In this study, a photonic Dirac-Weyl semimetal is proposed by introducing screw rotation symmetries into a spatial inversion symmetry-lacking system. A realistic metacrystal structure is designed for experimental consideration. The screw rotation symmetries are crucial for the existence of Dirac points, whose Z2 topology is revealed by the (010) surface states. Meanwhile, two pairs of ideal Weyl points at the same frequency are protected by D2d point group symmetries. The Dirac points and Weyl points reside in a clean frequency interval. The proposed photonic Dirac-Weyl semimetal provides a versatile platform for exploring the interaction between Dirac and Weyl semimetals and exploiting possible photonic topological devices.
Article
Physics, Multidisciplinary
Shaojie Ma, Hongwei Jia, Yangang Bi, Shangqiang Ning, Fuxin Guan, Hongchao Liu, Chenjie Wang, Shuang Zhang
Summary: Due to the chiral nature of Weyl nodes, a Weyl system exhibits one-way chiral zero modes under a magnetic field, which is known as the chiral anomaly. By coupling a Yang monopole with an external gauge field, we experimentally demonstrate the existence of a gapless chiral zero mode using an inhomogeneous Yang monopole metamaterial. The judiciously designed metallic helical structures and the corresponding effective antisymmetric bianisotropic terms enable control of gauge fields in a synthetic five-dimensional space.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Jipeng Wu, Rongzhou Zeng, Jiaojiao Liang, Di Huang, Xiaoyu Dai, Yuanjiang Xiang
Summary: In this study, a one-dimensional photonic crystal Fabry-Perot cavity containing a multi-Weyl semimetal (mWSM) defect is proposed to investigate spin-dependent perfect absorption. By adjusting different parameters, the perfect absorption wavelength of different spin waves can be conveniently controlled. These studies provide simple and effective approaches to acquire spin-dependent and adjustable perfect absorption.
Article
Optics
Hongwei Jia, Mudi Wang, Shaojie Ma, Ruo-Yang Zhang, Jing Hu, Dongyang Wang, Che Ting Chan
Summary: We propose an experimental scheme for realizing chiral Landau levels in a two-dimensional photonic system by introducing an inhomogeneous effective mass and breaking local parity-inversion symmetries. The synthetic in-plane magnetic field generated couples with the Dirac quasi-particles, inducing the zeroth-order chiral Landau levels and experimentally observing their one-way propagation characteristics. The robust transport of the chiral zeroth mode against defects in the system is also tested.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Yuexin Zhang, Chao Liu, Xiaoyu Dai, Yuanjiang Xiang
Summary: The concept of crystalline disclinations in solid-state physics has been researched, revealing novel topological phases and expanding the topological material family. However, there is a need to investigate the bulk-disclination correspondence in three-dimensional topological semimetals. We present an example of a higher-order Dirac semimetal in acoustic crystals with central disclinations, showing potential applications in acoustic devices and exploring high-performance three-dimensional acoustic metamaterials.
Proceedings Paper
Engineering, Electrical & Electronic
Massimo Moccia, Giuseppe Castaldi, Lei Zhang, Vincenzo Galdi, Tie Jun Cui
Summary: Space-time-coding digital metasurfaces offer significant potential for advanced field manipulations in the joint space-frequency-polarization domain, and for overcoming limitations in linear and time-invariant electromagnetic systems.
2023 17TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION, EUCAP
(2023)
Article
Nanoscience & Nanotechnology
Shiwen Chen, Yixuan Zeng, Zhongfu Li, Yu Mao, Xiaoyu Dai, Yuanjiang Xiang
Summary: This work demonstrates the achievement of nonreciprocal transmission and optical bistability for free-space propagation by incorporating Kerr nonlinearities into ultrathin optical metasurfaces. The symmetry-protected bound states in the continuum (BICs) ensure polarization-independent characteristics. Furthermore, the nonreciprocal intensity range can be adjusted by the structure parameters, making this design promising for optical switch, routing, and isolator applications.
Article
Multidisciplinary Sciences
Biye Xie, Renwen Huang, Shiyin Jia, Zemeng Lin, Junzheng Hu, Yao Jiang, Shaojie Ma, Peng Zhan, Minghui Lu, Zhenlin Wang, Yanfeng Chen, Shuang Zhang
Summary: This study proposes and demonstrates an approach to link non-trivial bulk topology to the partition of local density of states (LDOS) in multiple dimensions. In the context of photonic crystals, the authors observe that LDOS in non-trivial topological structures avoids the edges and corners, whereas in trivial structures, LDOS extends throughout the bulk area.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Changyou Luo, Yongqiang Kang, Xiaoyu Dai, Yuanjiang Xiang
Summary: In this paper, a cavity containing a unique medium is proposed to enhance the Goos-Hanchen shifts of light beams. The Goos-Hanchen shifts can be controlled by adjusting the intensity and detuning of the coherent control field, without modifying the material and structure of the dielectric interface. This work has significant potential for applications in optical devices, optical-beam steering and alignment, optical sensors, and optical switches.
IEEE PHOTONICS JOURNAL
(2023)
Article
Nanoscience & Nanotechnology
Qijun Ma, Xue Chen, Qisen Xiong, Leyong Jiang, Yuanjiang Xiang
Summary: The nonreciprocal surface modes in Weyl semimetal and the nonreciprocal photon occupation number on a graphene surface can be used to manipulate the nonreciprocal near-field energy transfer. In this study, the researchers investigated the near-field radiative heat flux transfer between a graphene heterostructure supported by a magnetic WSM and a twist-Weyl semimetal (T-WSM). They found that the transfer of near-field radiative heat flux can be caused by nonequilibrium fluctuations induced by drift currents. Furthermore, the interaction between nonreciprocal surface modes and the nonreciprocal photon occupation number in graphene allows for flexible manipulation of the near-field heat flux size and direction.
Article
Engineering, Electrical & Electronic
Jie Tang, Yuanjiang Xiang
Summary: This study systematically investigates the nonlinear optical response of indium selenide nanosheets and demonstrates their potential and application value in nanophotonic devices by creating logical gates and nonlinear isolators based on them.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
