Article
Optics
Kun Zhang, Yan Liu, Shixia Li, Feng Xia, Weijin Kong
Summary: This work introduces an actively tunable bi-functional metamirror based on a bi-layer graphene structure, which can achieve spin-selective absorption and polarization conversion under different polarization conditions, with stable performance.
Article
Optics
Xiangyang Wang, Ming Chen, Wanli Zhao, Xinyu Shi, Wenhao Han, Renjie LI, Jinbiao Liu, Chuanxin Teng, Shijie Deng, Yu Cheng, Libo Yuan
Summary: In this study, a chiral subwavelength mirror composed of C-shaped metal split ring and L-shaped vanadium dioxide (VO2) is proposed to address the issues of narrow working bandwidth, low efficiency, and complex structure in existing terahertz chiral absorption. Theoretical results show that the chiral metamirror exhibits a circular dichroism (CD) value greater than 0.9 at 5.70 to 8.55 THz, with a maximum value of 0.942 at f = 7.18 THz. By adjusting the conductivity of VO2, the CD value can be continuously adjustable from 0 to 0.942, allowing for free switching of the CD response between the on and off states. Additionally, the CD modulation depth exceeds 0.99 in the range of 3 to 10 THz. The proposed chiral metamirror has important reference value in the terahertz range for constructing chiral light detectors, CD metamirrors, switchable chiral absorbers, and spin-related systems. This work provides a new idea for improving the terahertz chiral metamirror operating bandwidth and promotes the development of terahertz broadband tunable chiral optical devices.
Article
Physics, Multidisciplinary
Yuya Ikeda, Sota Kitamura, Takahiro Morimoto
Summary: A bicircular light (BCL) is composed of left and right circularly polarized lights with different frequencies, and can generate a photocurrent in centrosymmetric systems by introducing an effective polarity to the system. Formulas for the BCL-induced photocurrent are derived using standard perturbation theory, and are applied to a simple 1D model and 3D Dirac and Weyl semimetals. The nonperturbative effect at high light intensity is also discussed using the Floquet technique.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Y. J. Jin, Z. J. Chen, X. L. Xiao, H. Xu
Summary: The study reveals that spin-1 Weyl points can transform into quadratic Weyl points depending on symmetry variation, providing new insights into the transition among unconventional quasiparticles.
Article
Multidisciplinary Sciences
Erjian Cheng, Wei Xia, Xianbiao Shi, Hongwei Fang, Chengwei Wang, Chuanying Xi, Shaowen Xu, Darren C. Peets, Linshu Wang, Hao Su, Li Pi, Wei Ren, Xia Wang, Na Yu, Yulin Chen, Weiwei Zhao, Zhongkai Liu, Yanfeng Guo, Shiyan Li
Summary: The study on magnetic topological semimetals found that magnetism-induced topological transition in EuAs3 from a topological nodal-line semimetal to a topological massive Dirac metal. The topological nature in different states was verified by electrical transport measurements and angle-resolved photoemission spectroscopy. Additionally, an extremely large magnetoresistance and a temperature-induced Lifshitz transition were observed, indicating a rich platform for exploring exotic physics.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Zheng Ren, Hong Li, Shrinkhala Sharma, Dipak Bhattarai, He Zhao, Bryan Rachmilowitz, Faranak Bahrami, Fazel Tafti, Shiang Fang, Madhav Prasad Ghimire, Ziqiang Wang, Ilija Zeljkovic
Summary: The interplay of magnetism and electronic band topology can create and control novel electronic phenomena in unconventional magnets. In this study, we used scanning tunneling microscopy and spectroscopy to observe unique spectroscopic features in a prototypical magnet. These features are consistent with the predicted low-energy Weyl fermions and associated topological Fermi arc surface states. By measuring their response to magnetic fields, we discovered an evolution in energy based on magnetization direction. Electron scattering and interference imaging further demonstrated the tunability of related electronic states. Our experiments directly visualize how spin reorientation affects the electronic density of states of the Weyl fermion band structure. Combined with previous research, our work establishes this magnet as an interesting platform for a wide range of topological and correlated electron phenomena.
NPJ QUANTUM MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Qi Shen, Han Xiong
Summary: This study proposes and numerically analyzes a perfect THz metamaterial absorber based on BDS and STO. By integrating two new materials with adjustable dielectric constant in one structure, the performance of this design can be flexibly controlled. Further research proves that this designed absorber shows outstanding feature of angular insensitivity.
RESULTS IN PHYSICS
(2022)
Article
Optics
Yan Cheng, Wenhan Cao, Guangqing Wang, Xiaoyong He, Fangting Lin, Feng Liu
Summary: By depositing a trapezoidal dielectric stripe on a 3D Dirac semimetal hybrid plasmonic waveguide, the thermal tunable propagation properties in the terahertz regime were systematically investigated. The results show that the width of the trapezoidal stripe affects the propagation length and figure of merit (FOM), with both decreasing as the upper side width increases. The propagation properties are also strongly influenced by temperature, with a modulation depth of more than 96% within the range of 3-600 K.
Article
Physics, Multidisciplinary
Chunzhen Fan, Peiwen Ren, Yuanlin Jia, Shuangmei Zhu, Junqiao Wang
Summary: Based on Dirac semimetal metamaterials, this research investigated the tunable plasmon induced transparency (PIT) phenomenon, revealing a pronounced transparency window that can be dynamically adjusted with Fermi energy. The transparency window exhibits a distinct blue shift with larger Fermi energy and can be switched on and off with different polarization angles. Additionally, a small variation of the refractive index of the substrate can induce a clear movement of the PIT transparency window, providing guidance for optical sensing applications.
Article
Materials Science, Multidisciplinary
Satyabrata Bera, Sudipta Chatterjee, Subhadip Pradhan, Suman Kalyan Pradhan, Sk Kalimuddin, Arnab Bera, Ashis K. Nandy, Mintu Mondal
Summary: In this study, we report a near room temperature 2D ferromagnet that shows a large anomalous Hall conductivity, which is attributed to the unique electronic structure and spin-orbit coupling effect. This material has the potential for important applications in spintronics.
Article
Chemistry, Analytical
Mengjiao Ren, Chengpeng Ji, Xueyan Tang, Haishan Tian, Leyong Jiang, Xiaoyu Dai, Xinghua Wu, Yuanjiang Xiang
Summary: In this paper, a sensitivity-tunable terahertz (THz) liquid/gas biosensor based on a coupling prism-three-dimensional Dirac semimetal (3D DSM) multilayer structure is studied. The high sensitivity of the biosensor is attributed to the sharp reflected peak caused by surface plasmon resonance (SPR) mode. The reflectance of the biosensor can be modulated by the Fermi energy of 3D DSM, resulting in tunable sensitivity. After parameter optimization, the sensitivity of the liquid biosensor reaches over 100°/RIU. This simple structure provides a reference idea for achieving high sensitivity and tunable biosensor devices.
Article
Chemistry, Multidisciplinary
Qian Xia, Na Li, Wei-Xiao Ji, Chang-Wen Zhang, Meng Ding, Miao-Juan Ren, Sheng-Shi Li
Summary: In this paper, a 2D AlSb monolayer is proposed as an excellent candidate for two-dimensional nodal-loop semimetals (NLSM) through systematic first-principles calculations. The AlSb monolayer exhibits fascinating multiple nodal-loop states due to the crossing of conduction and valence bands, which are protected by its glide mirror symmetry. The transport properties of the AlSb monolayer under in-plane uniaxial strains are also investigated, and it is found that both compressive and tensile strains improve its transporting properties.
Article
Chemistry, Multidisciplinary
David Reger, Philipp Haines, Konstantin Y. Amsharov, Julia A. Schmidt, Tobias Ullrich, Simon Boenisch, Frank Hampel, Andreas Goerling, Jenny Nelson, Kim E. Jelfs, Dirk M. Guldi, Norbert Jux
Summary: A straightforward synthetic route was designed to create a family of pi-extended helicenes called superhelicenes. By altering the 5-membered ring, a versatile library of molecular building blocks was realized, allowing for easy tuning of both structure and features. Physico-chemical characterizations confirmed the concept, showing potential for outstanding hole transporting properties in charge-carrier mobilities.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Astronomy & Astrophysics
Katsumasa Nakayama, Kei Suzuki
Summary: The Casimir effect is a quantum phenomenon caused by the zero-point energy of relativistic fields in a finite-size system. While this effect has been extensively studied in photon fields, its counterpart in fermion fields in Dirac/Weyl semimetals remains an open question. In this study, we theoretically demonstrate the characteristics of the Casimir effect in relativistic electron fields in Dirac/Weyl semimetals, using an effective Hamiltonian for realistic materials such as Cd3As2 and Na3Bi. We observe an oscillation of the Casimir energy with the thickness of the thin film, which is attributed to the existence of Dirac/Weyl nodes in momentum space. This effect can be experimentally observed in thin films of semimetals, where the thickness-dependent thermodynamic quantities are influenced by the Casimir energy.
Article
Chemistry, Multidisciplinary
Botao Fu, Xiaotong Fan, Si Li, Da-Shuai Ma, Run-Wu Zhang, Cheng-Cheng Liu
Summary: This study demonstrates the hydrogenation can solve common problems in two-dimensional borophene, such as stability and applicability. By introducing a ladder-like boron hydride sheet, named as 2D ladder polyborane, an ideal scenario with an anisotropic and tilted Dirac cone can be achieved, which can be fully described by a minimal two-band tight-binding model. External fields, such as an electric field or a circularly polarized light field, can effectively induce distinctive massive Dirac fermions, and four types of multi-field-driven topological domain walls with tunable chirality and valley indexes are further established. Moreover, the 2D ladder polyborane is thermodynamically stable at room temperature and supports highly switchable Dirac fermions, providing an ideal platform for realizing and exploring various multi-field-tunable electronic states.
Article
Physics, Applied
Yong Li, Xiang Zhai, Shengxuan Xia, Hongjian Li, Lingling Wang
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2020)
Article
Optics
Shengxuan Xia, Xiang Zhai, Lingling Wang, Shuangchun Wen
Article
Optics
Sheng-Xuan Xia, Xiang Zhai, Ling-Ling Wang, Shuang-Chun Wen
Article
Nanoscience & Nanotechnology
Jingrui Guan, Shengxuan Xia, Zeyan Zhang, Jing Wu, Haiyu Meng, Jing Yue, Xiang Zhai, Lingling Wang, Shuangchun Wen
NANOSCALE RESEARCH LETTERS
(2020)
Article
Optics
Hongju Li, Yu Zhang, Haixiao Xiao, Meng Qin, Shengxuan Xia, Lingling Wang
Article
Physics, Applied
Ting Zhou, Shuai Wang, Yanzi Meng, Shiyu Wang, Yanghong Ou, Hongjian Li, Huangqing Liu, Xiang Zhai, Shengxuan Xia, Lingling Wang
Summary: The composite metasurface made of InSb strips and SiO2 substrate achieves multi-band coherent perfect absorption in the terahertz frequency range. By controlling the relative phase or intensity, absorption at each resonance frequency can be independently modulated. The design also exhibits thermal tunability and sensitivity to refractive index, making it suitable for sensing applications in the terahertz band.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Sang Hyun Park, Shengxuan Xia, Sang-Hyun Oh, Phaedon Avouris, Tony Low
Summary: In this study, the coupling of plasmons and vibrational modes in a model system of molecular layers on graphene was investigated using a non-Hermitian framework. It was found that the transition point between strong and weak coupling regimes coincides with the exceptional point of non-Hermitian physics. By changing the incident angle of light and the graphene Fermi energy, the exceptional point can be conveniently located, leading to enhanced spectral sensitivity with small changes in molecular film thickness.
Article
Optics
Zhiyong Wang, Yanghong Ou, Shiyu Wang, Yanzi Meng, Zi Wang, Xiang Zhai, Lingling Wang, Shengxuan Xia
Summary: In this paper, an easy-to-implement metamaterial absorber based on bulk Dirac semimetal is presented. The device achieves ultrahigh quality factor and excellent sensing performance, with precise control over resonance wavelength by adjusting the parameters. It has high-performance applications in terahertz filtering, detection, and biochemical sensing.
Article
Optics
Wenfeng Xiao, Yanghong Ou, Shiyu Wang, Shuai Wang, Yanzi Meng, Xiang Zhai, Shengxuan Xia, Lingling Wang
Summary: In this paper, a metamaterial sensor based on stacking gold and silicon dioxide is proposed, which achieves narrow-band absorption and improved figure of merit. The sensor exhibits excellent sensing performance and benefits the design of multi-band photodetectors and high-sensitivity sensors due to its mature manufacturing technology.
Article
Optics
Sheng-xuan Xia, Di Zhang, Zizhuo Zheng, Xiang Zhai, Hongju Li, Jian-qiang Liu, Ling -Ling Wang, Shuang-chun Wen
Summary: In this Letter, the theoretical study of topological plasmons in Su-Schrieffer-Heeger (SSH) model-based graphene nanoribbon (GNR) layers is conducted. It is found that in the one-dimensional (1D) stacked case, only two topological modes exist, with the field localized in the top or bottom layer, as predicted by the Zak phase. Expanding the stacked 1D GNR layers to two-dimensional (2D) arrays in the in-plane direction, the topology is characterized by the 2D Zak phase, predicting the emergence of three kinds of topological modes: topological edge, surface, and corner modes. This work provides a platform for realizing topological modes in GNRs and has importance for the design of topological photonic devices such as lasers and sensors.
Article
Physics, Applied
Sheng-Xuan Xia, Di Zhang, Xiang Zhai, Ling-Ling Wang, Shuang-Chun Wen
Summary: In this Letter, the authors report on phase-controlled topological plasmons in 1D graphene nanoribbons based on a variant of the Su-Schrieffer-Heeger (SSH) model. They investigate the normal SSH model and reveal the existence of edge modes with nontrivial topology, which exhibit strong field confinement and extreme frequency stability. The authors also introduce an offset SSH model variant that allows for engineering the width of the topological gap and the number of topological windows. The findings provide insight into the physics of topologically protected graphene plasmons and offer potential applications in designing plasmon devices with immunity to structural imperfections.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Zhengdao Xie, Guoli Li, Shengxuan Xia, Chang Liu, Sen Zhang, Zhouxiaosong Zeng, Xingqiang Liu, Denis Flandre, Zhiyong Fan, Lei Liao, Xuming Zou
Summary: This paper examines the ultimate limit in optoelectronic performances of monolayer WSe2 FETs by constructing a sloping channel. By using a simple scaling method compatible with current micro/nanofabrication technologies, a record-high saturation current of 1.3 mA/μm at room temperature is achieved, surpassing any reported monolayer 2D semiconductor transistors. Additionally, quasi-ballistic transport and high saturation velocity make WSe2 FETs suitable for extremely sensitive photodetectors.
Article
Materials Science, Multidisciplinary
Shengxuan Xia, Xiang Zhai, Lingling Wang, Yuanjiang Xiang, Shuangchun Wen
Summary: In this paper, a theoretical scheme is proposed to achieve unidirectional odd-to-even order plasmonically induced transparency (PIT) by establishing a model with two layers of periodic graphene nanoribbons. The underlying physical principles are uncovered by predicting the positions of phase difference, and the proposed PIT concept is demonstrated to have good robustness against both ribbon width and relative ribbon positions.
Article
Materials Science, Multidisciplinary
Hongju Li, Gangao Wei, Hongmiao Zhou, Haixiao Xiao, Meng Qin, Shengxuan Xia, Feng Wu
Summary: This study demonstrates a specially designed TMD Huygens metasurface that overcomes the absorption limit of a subwavelength thin film, achieving a super-high absorption rate of up to 87%. The metasurface can control the absorption rate throughout the entire near-infrared region, regardless of polarization and angle, offering important potential applications.
