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The 3,6-Dimethoxythieno[3,2-B]Thiophene-Based Bifunctional Electrodes for High-Performance Electrochromic Supercapacitors Prepared by One-Step Electrodeposition

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SSRN

SSRN 2024年

作者： Yu, Zhixuan Wang, Rui Tang, Huayu Zheng, Ding Yu, Junsheng State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu610054 China

An integrated visual energy system consisting of conjugated polymer electrodes is promising for combining electrochromism with energy storage. In this work, we obtained copolymer bifunctional electrodes poly(3,6-dimethoxythieno[3,2-b]thiophene-co-2,3-dihydrothieno[3,4-b][1,4]dioxin-3-ylmethanol)(P(TT-OMe-co-EDTM)) by one-step electrochemical copolymerization, which exhibits favorable electrochromic and capacitive energy storage properties. Because of the synergistic effect of PTT-OMe and PEDTM, the prepared copolymers show better flexibility. Moreover, the morphology and electrochemical properties of the copolymers could be adjusted by depositing different molar ratios of 3,6-dimethoxythieno[3,2-b]thiophene (TT-OMe) and 2,3-dihydrothieno[3,4-b][1,4] dioxin-3-ylmethanol (EDTM). The P(TT-OMe-co-EDTM) electrodes realized high specific capacitance (190 F/g at 5 mV/s), recognizable and tunable color conversion. This work provides a novel and simple way to synergistically improve electrochromic and energy storage properties and develop thiophene-based conducting polymers for electrochromic energy storage devices. © 2024, The Authors. All rights reserved.

关键词： Electrochromism

High Performance Hydrogen Sensors Based on Tellurium Nanobelt Field-Effect Transistors

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High Performance Hydrogen Sensors Based on Tellurium Nanobel...

IEEE SENSORS

作者： Yu Guo Jianping Zhang Zhen Yuan Huiling Tai State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China (UESTC) Chengdu China

ISBN: (数字)9798350363517

ISBN: (纸本)9798350363524

Tellurium (Te), a p-type semiconductor with high carrier mobility, is particularly advantageous for field-effect transistor (FET) applications. In this study, a high-performance FET-type hydrogen sensor utilizing Te nanobelts was developed. The sensor was fabricated with a palladium (Pd) gate, specifically chosen for its sensitivity to hydrogen, enhancing both selectivity and response. The results indicate a short response time of ~2 s to 4% H 2 , a detection limit as low as 50 ppm, and negligible cross-sensitivity at room temperature, highlighting the potential of Te in advancing gas sensor technology. Furthermore, the flexible FET design is expected to detect various gases, broadening the application potential of Te-based gas sensors.

关键词： Temperature sensors Sensitivity Hydrogen Field effect transistors Logic gates Palladium Sensors Time factors Gas detectors Tellurium

Polarization splitter-rotator on thin film lithium niobate based on multimode interference

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arXiv 2024年

作者： Wang, Mengke Yao, Hao Deng, Jiayao Hu, Zhefeng Tang, Tingting Chen, Kaixin School of optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu610054 China Optoelectronic Sensor Devices and Systems Key Laboratory of Sichuan Provincial University Chengdu University of Information Technology Sichuan Chengdu610225 China

Polarization splitter-rotators (PSRs) are the key elements to realize on-chip polarization manipulation. Current PSRs on thin film lithium niobate (TFLN) rely on sub-micron gaps to realize modes separation, which increase the difficulties of lithography and etching. In this paper, a polarization splitter-rotator on TFLN based on multimode interference (MMI) is demonstrated. Mode division is achieved by an MMI-based mode demultiplexer. The feature size of the PSR is 1.5 μm, which can be fabricated with low priced i-line contact aligners. Experimental results show a polarization extinction ratio (PER) > 20 dB and insertion loss (IL) 9.5 dB and an IL Copyright © 2024, The Authors. All rights reserved.

关键词： Thin films

Magnetization Plateaus in the Two-dimensional S = 1/2 Heisenberg Model with a 3×3 Checkerboard Structure

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arXiv 2024年

作者： Liang, Xuyang Yao, Dao-Xin Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies Center for Neutron Science and Technology School of Physics Sun Yat-Sen University Guangzhou510275 China

We investigate the S=1/2 antiferromagnetic Heisenberg model with a 3×3 checkerboard lattice structure in a longitudinal magnetic field. By using the stochastic series expansion quantum Monte Carlo (SSE-QMC) method, we obtain the properties of the non-plateau XY phase, 1/9, 3/9, 5/9, 7/9 magnetization plateau phases, and fully polarized phase. Then, we determine the precise phase transition critical points belonging to the 3D XY universality class through finite-size scaling. Moreover, we study the longitudinal and transverse dynamic spin structure factors of this model in different phases. For the non-plateau XY phase, the energy spectra present a gap between the low-energy gapless branch and the high-energy part under the competition of magnetic field and interaction. The gapless branch can be described by the spin wave theory in the canted antiferromagnetic phase of the effective "block spin" model. In the magnetization plateau phase, we identify that the excitation arises from localized disturbances within the sublattice, which are capable of spreading in momentum space. This study offers theoretical insights and interpretations for the characteristics of the ground state and the inelastic neutron scattering spectrum in two-dimensional quantum magnetic materials. Specifically, it focuses on materials with a checkerboard unit cell structure and odd-spin configurations under the influence of a longitudinal magnetic field. Copyright © 2024, The Authors. All rights reserved.

关键词： Stochastic systems

Dirac points and Weyl phase in a honeycomb altermagnet

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arXiv 2024年

作者： Zhang, Meng-Han Guo, Xuan Yao, Dao-Xin Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies Center for Neutron Science and Technology School of Physics Sun Yat-Sen University Guangzhou510275 China

We present a graphene derivative displaying novel topological phenomena without the spin-orbit coupling (SOC) in a collinear altermagnet. Band degeneracies in spin-split honeycomb antiferromagnets produce unique distribution patterns of Berry curvature and give rise to topological boundary states with unconventional spin textures. The asymmetric Berry curvature due to spin splitting can be created by lifting the degeneracies, which concentrate intensely at Weyl points contributing to carrier dynamics with a large valley Hall effect. The altermagnetism breaks the intrinsic time-reversal symmetry, guaranteeing the formation of pairs of Weyl points associated with the internal spin structure chiralities. We investigate the evolution of Dirac and Weyl crossings, in which topological phase transitions are characterized by the high Chern numbers preserving the non-intersecting flows of Wannier centers over occupied bands. Our results yield unique degeneracy-protected states by leveraging the symmetry constraints, where corresponding experiments are illustrated to demonstrate the potential of advancing valleytronic devices via unconventional topological responses. Copyright © 2024, The Authors. All rights reserved.

关键词： Honeycomb structures

Topological magnons in a collinear altermagnet

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arXiv 2024年

作者： Zhang, Meng-Han Xiao, Lu Yao, Dao-Xin Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies Center for Neutron Science and Technology School of Physics Sun Yat-sen University Guangzhou510275 China

We propose a model with Weyl magnons and nodal-line magnons (Z2) in a collinear altermagnet on the honeycomb lattice. Altermagnetic magnon bands can be realized by breaking the symmetry of the second nearest neighbor exchange couplings without the Dzyaloshinskii-Moriya interaction (DMI). In addition to the Chern number and Z2 invariant, chirality is important to describe the magnon topology. The model shows the nonzero magnon spin Nernst effect when a longitudinal temperature gradient exists. We calculate the differential gyromagnetic ratio induced purely by the topology of altermagnetic magnons, which can be probed through the Einstein-de Haas (EdH) effect. © 2024, CC BY.

关键词： Topology

Einstein-de Haas effect: a bridge linking mechanics, magnetism, and topology

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arXiv 2024年

作者： Nie, Xin Yao, Dao-Xin Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies Center for Neutron Science and Technology School of Physics Sun Yat-Sen University Guangzhou510275 China

The Einstein-de Haas (EdH) effect is a fascinating phenomenon that links mechanics and magnetism. Despite being discovered over a century ago, it remains significant in contemporary science, particularly within the fields of spintronics and ultrafast magnetism. Recent predictions suggest that the EdH effect may be realized in topological magnon systems, potentially leading to even richer properties. In this perspective, we introduce recent advancements in the EdH effect and discuss its developments in three key aspects: the microscopic mechanism, its manifestation in topological systems, and chirality-selective magnon-phonon coupling. Our discussions aim to inspire further explorations of the EdH effect and highlight its promising applications in different areas. Copyright © 2024, The Authors. All rights reserved.

关键词： Statistical mechanics

High efficiency and ultra-broadband suspended grating coupler on ultra-thin lithium niobate on insulator

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Optics Express 2025年第13期33卷 28226-28232页

作者： Jindong Lu Guanyu Chen Wenqu Su Haibo Li Xiaowen Gu Hua Yu Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education) Chongqing University Chongqing 400044 China College of Optoelectronic Engineering Chongqing University Chongqing 400044 China Institute of Advanced Interdisciplinary Studies Chongqing University Chongqing 400044 China Key Laboratory of Photonic-Electronic Integration and Communication-Sensing Convergence (Southwest Jiaotong University) Ministry of Education Chengdu 611756 China National Key Laboratory of Solid-State Microwave Devices and Circuits Nanjing 210008 China Nanjing Electronic Devices Institute Nanjing 210008 China gxw_tk@*** yuhua@***

We propose and demonstrate a high-performance suspended grating coupler on ultra-thin X-cut lithium niobate on insulator (LNOI) for fully-etched photonic devices. The optimized design achieves exceptional coupling efficiency (-3.5 dB at 1546.24 nm), a broad bandwidth (1 dB bandwidth of 70 nm and 3 dB bandwidth exceeding 90 nm), and robust fabrication tolerance. This work addresses a critical challenge in integrated photonics by enabling efficient grating couplers on ultra-thin LNOI platforms, thereby providing a practical and scalable solution for coupling light into photonic crystal waveguides and other suspended photonic devices.

关键词： Effective refractive index Grating coupler Integrated photonics Lithium niobate Photonic crystal waveguides Photonic devices

Correlation effects in a simplified bilayer two-orbital Hubbard model at half filling

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arXiv 2024年

作者： Yang, Jian-Jian Yao, Dao-Xin Wu, Han-Qing Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies Center for Neutron Science and Technology School of Physics Sun Yat-sen University Guangzhou510275 China

Motivated by the discovery of high-temperature superconductivity in bilayer nickelate La3Ni2O7 under pressure, we investigate the ground-state phase diagram and correlation effects using determinant quantum Monte Carlo simulations in a simplified bilayer two-orbital Hubbard model at half filling. Our results reveal the emergence of a nonmagnetic weakly insulating phase at weak on-site Hubbard interactions, transitioning to an antiferromagnetic Mott insulating phase as the interaction strength exceeds a critical value U/tx1 ≈ 4.15. This phase transition is consistent with the 3D O(3) Heisenberg universality class. Additionally, we analyze dynamical properties such as the single-particle spectral function and dynamic spin structure factor. The pronounced inter-layer correlation of d3z2−r2 orbitals results in a downward trend and an extended flatness in the γ band, mirroring the angle-resolved photoemission spectroscopy findings under ambient pressure. Our numerical results provide important clues for understanding the strong correlation effects in La3Ni2O7 Copyright © 2024, The Authors. All rights reserved.

关键词： Ground state