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Ion irradiation induced crystalline disorder accelerates interfacial phonon conversion and reduces thermal boundary resistance

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Physical Review B 2024年第16期109卷 165421-165421页

作者： Thomas W. Pfeifer Henry Aller Eric R. Hoglund Ethan A. Scott John A. Tomko Habib Ahmad Alan Doolittle Ashutosh Giri Khalid Hattar Alan J. H. McGaughey Patrick E. Hopkins Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville Virginia 22904 USA Department of Mechanical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA Department of Materials Science and Engineering University of Virginia Charlottesville Virginia 22904 USA Sandia National Laboratories Albuquerque New Mexico 87185 USA School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta Georgia 30332 USA Center for Advanced Electronics & Photovoltaic Engineering IIUI Islamabad Department of Mechanical Industrial and Systems Engineering University of Rhode Island Kingston Rhode Island 02881 USA Department of Nuclear Engineering University of Tennessee Knoxville Tennessee 37996 USA Department of Physics University of Virginia Charlottesville Virginia 22904 USA

Traditional understanding of the thermal boundary resistance (TBR) across solid-solid interfaces posits that the vibrational densities of states overlap between materials dictates interfacial energy transport, with phonon scattering occurring at the interface. Using atomistic simulations, we show a mechanism for control of TBR; point defects near an interface can lead to both short- and midrange disorder, accelerating the conversion of vibrational energy between bulk and interfacial modes, ultimately reducing the TBR. We experimentally demonstrate this reduction through ion irradiation of gallium nitride and subsequently measuring the TBR across Al/GaN interfaces.

关键词： Crystal defects Defects Irradiation effects Lattice dynamics Phonons Thermal boundary conductance Vibrational states Interfaces Semiconductor compounds Transducers Ion implantation Molecular dynamics Thermoreflectance

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Two Birds With One Stone: Enhancing Communication and Sensing via Multi-Functional RIS

arXiv

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arXiv 2024年

作者： Ni, Wanli Wang, Wen Zheng, Ailing Wang, Peng You, Changsheng Eldar, Yonina C. Niyato, Dusit Schober, Robert The Department of Electronic Engineering Tsinghua University Beijing100084 China The Pervasive Communications Center Purple Mountain Laboratories Nanjing211111 China The State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China The School of Electrical and Electronic Engineering North China Electric Power University Beijing102206 China The Department of Electronic and Electrical Engineering Southern University of Science and Technology Shenzhen518055 China The Faculty of Mathematics and Computer Science Weizmann Institute of Science Israel The College of Computing and Data Science Nanyang Technological University Singapore Erlangen91054 Germany

In this article, we propose new network architectures that integrate multi-functional reconfigurable intelligent surfaces (MF-RISs) into 6G networks to enhance both communication and sensing capabilities. Firstly, we elaborate how to leverage MF-RISs for improving communication performance in different communication modes including unicast, mulitcast, and broadcast and for different multi-access schemes. Next, we emphasize synergistic benefits of integrating MF-RISs with wireless sensing, enabling more accurate and efficient target detection in 6G networks. Furthermore, we present two schemes that utilize MF-RISs to enhance the performance of integrated sensing and communication (ISAC). We also study multi-objective optimization to achieve the optimal trade-off between communication and sensing performance. Finally, we present numerical results to show the performance improvements offered by MF-RISs compared to conventional RISs in ISAC. We also outline key research directions for MF-RIS under the ambition of 6G. Copyright © 2024, The Authors. All rights reserved.

关键词： Reconfigurable architectures

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Evaluating the Robustness of Complementary Channel Ferroelectric FETs Against Total Ionizing Dose Towards Radiation-Tolerant Embedded Nonvolatile Memory

TechRxiv

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TechRxiv 2023年

作者： Jiang, Zhouhang Guo, Zixiang Luo, Xuyi Sayed, Munazza Faris, Zubair Mulaosmanovic, Halid Duenkel, Stefan Soss, Steven Beyer, Sven Gong, Xiao Kurinec, Santosh Narayanan, Vijaykrishnan Amrouch, Hussam Zhang, Enxia Fleetwood, Daniel M. Schrimpf, Ronald D. Ni, Kai The Microsystems Engineering Ph.D. Program The Mechanical Engineering Rochester Institute of Technology RochesterNY14623 United States The Department of Electrical and Computer Engineering Vanderbilt University NashvilleTN37235 United States University of Stuttgart Stuttgart70174 Germany Germany The Munich Institute of Robotics and Machine Intelligence Arcisstrasse 21 Munich80333 Germany The GlobalFoundries Fab1 LLC Dresden Germany The Department of Electrical Computer Engineering National University of Singapore 119077 Singapore The Department of Computer Science and Engineering Penn State University University ParkPA16802 United States The Department of Electrical and Microelectric Engineering Rochester Institute of Technology RochesterNY14623 United States

In this work, a thorough assessment of the robustness of complementary channel HfO2 ferroelectric FET (FeFET) against total ionizing dose (TID) radiation is conducted, with the goal of determining its suitability for use as high-performance and energy-efficient embedded nonvolatile memory (eNVM) for space applications. We demonstrate that: i) ferroelectric HfO2 thin film is robust against X-ray and proton irradiation;ii) FeFET exhibits a polarization state dependent radiation sensitivity where the high-VTH (HVT) state sees noticeable negative VTH shift and low-VTH (LVT) is immune to irradiation, irrespective of the channel type;iii) the state dependence is ascribed to the depolarization field in the HVT, which points toward the channel and facilitates the transport and trapping of radiation-generated holes close to the channel. In the future, radiation hardening techniques need to be considered. © 2023, CC BY.

关键词： Radiation effects

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Synthetic materials with high pockels coefficient for plasmonic modulators

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Optical Materials Express 2025年第6期15卷 1356-1370页

作者： Killian Keller Marco Dober Joel Winiger Arnaud Schneuwly Zhuoyang Yu Michael Baumann Michael Doderer Shiro Nishiwaki Yaroslav E Romanyuk Jacob B Khurgin Juerg Leuthold Institute of Electromagnetic Fields (IEF) ETH Zürich Gloriastrasse 35 8092 Zurich Switzerland kkeller@ethz.ch Now with Department of Materials Science and Engineering National University of Singapore 9 Engineering Drive 1 #03-09 EA 117575 Singapore Laboratory of Thin Films and Photovoltaics Empa – Swiss Federal Laboratories for Materials Science and Technology Überlandstrasse 129 8600 Dübendorf Switzerland Department of Electrical and Computer Engineering John Hopkins Whiting School of Engineering 3400 North Charles Street Baltimore MD 21218 USA juerg.leuthold@ief.ee.ethz.ch

We present simulations of Pockels materials based on nonlinearities arising from intersubband transitions (ISBT). To elevate the Pockels coefficient to the order of nm/V, the ISBT resonance is tuned close to the operation point. This comes at the expense of increased material losses due to quasi-resonant operation. Such Pockels materials are of high interest for implementation in plasmonic modulators. In these modulators the higher material losses do not significantly impact the device performance, as overall losses are dominated by plasmonic waveguide losses. With this approach, voltage-loss-length ( V π Lα ) products on the order of ∼15 V dB may be achieved with plasmonic losses. Such efficiencies are comparable to those with photonic modulators. The Pockels effect coefficient calculations have been performed using self-consistent Schrödinger-Poisson simulations with consideration of many-body effects. Furthermore, we investigated the influence of RF field screening and surface roughness on the efficiency of the ISB transition-mediated Pockels *** by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License . Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

关键词： Absorption coefficient Electrooptical effects Optical activity Optical rectification Plasmon waveguides Pockels effect

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Applying classical control techniques to quantum systems: entanglement versus stability margin and other limitations

Applying classical control techniques to quantum systems: en...

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IEEE Conference on Decision and Control

作者： C. A. Weidner S. G. Schirmer F. C. Langbein E. Jonckheere H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering Quantum Engineering Technology Laboratories University of Bristol United Kingdom Faculty of Science & Engineering Swansea University Swansea UK School of Computer Science and Informatics Cardiff University Cardiff UK Department of Electrical and Computer Engineering University of Southern California Los Angeles CA USA

ISBN: (数字)9781665467612

ISBN: (纸本)9781665467629

Development of robust quantum control has been challenging and there are numerous obstacles to applying classical robust control to quantum system including bilinearity, marginal stability, state preparation errors, nonlinear figures of merit. The requirement of marginal stability, while not satisfied for closed quantum systems, can be satisfied for open quantum systems where Lindbladian behavior leads to non-unitary evolution, and allows for nonzero classical stability margins, but it remains difficult to extract physical insight when classical robust control tools are applied to these systems. We consider a straightforward example of the entanglement between two qubits dissipatively coupled to a lossy cavity and analyze it using the classical stability margin and structured perturbations. We attempt, where possible, to extract physical insight from these analyses. Our aim is to highlight where classical robust control can assist in the analysis of quantum systems and identify areas where more work needs to be done to develop specific methods for quantum robust control.

关键词： Robust control Quantum system Perturbation methods Qubit Stability analysis Behavioral sciences

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Sample-efficient model-based reinforcement learning for quantum control

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Physical Review Research 2023年第4期5卷 043002-043002页

作者： Irtaza Khalid Carrie A. Weidner Edmond A. Jonckheere Sophie G. Schirmer Frank C. Langbein School of Computer Science and Informatics Cardiff University Cardiff CF24 4AG United Kingdom Quantum Engineering Technology Laboratories H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering University of Bristol Bristol BS8 1FD United Kingdom Department of Electrical and Computer Engineering University of Southern California Los Angeles California 90007 USA Department of Physics Swansea University Swansea SA2 8PP United Kingdom

We propose a model-based reinforcement learning (RL) approach for noisy time-dependent gate optimization with reduced sample complexity over model-free RL. Sample complexity is defined as the number of controller interactions with the physical system. Leveraging an inductive bias, inspired by recent advances in neural ordinary differential equations (ODEs), we use an autodifferentiable ODE, parametrized by a learnable Hamiltonian ansatz, to represent the model approximating the environment, whose time-dependent part, including the control, is fully known. Control alongside Hamiltonian learning of continuous time-independent parameters is addressed through interactions with the system. We demonstrate an order of magnitude advantage in sample complexity of our method over standard model-free RL in preparing some standard unitary gates with closed and open system dynamics, in realistic computational experiments incorporating single-shot measurements, arbitrary Hilbert space truncations, and uncertainty in Hamiltonian parameters. Also, the learned Hamiltonian can be leveraged by existing control methods like GRAPE (gradient ascent pulse engineering) for further gradient-based optimization with the controllers found by RL as initializations. Our algorithm, which we apply to nitrogen vacancy (NV) centers and transmons, is well suited for controlling partially characterized one- and two-qubit systems.

关键词： Machine learning Open quantum systems & decoherence Quantum computation Quantum control Quantum feedback Quantum information processing Quantum information theory Quantum parameter estimation Quantum tomography

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DeceFL:a principled fully decentralized federated learning framework

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National science Open 2023年第1期2卷 35-51页

作者： Ye Yuan Jun Liu Dou Jin Zuogong Yue Tao Yang Ruijuan Chen Maolin Wang Chuan Sun Lei Xu Feng Hua Yuqi Guo Xiuchuan Tang Xin He Xinlei Yi Dong Li Guanghui Wen Wenwu Yu Hai-Tao Zhang Tianyou Chai Shaochun Sui Han Ding School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Applied Mathematics University of WaterlooWaterloo N2L 3G1Canada State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110819China School of Mathematical and Physical Sciences Wuhan Textile UniversityWuhan 430200China School of Electrical Engineering and Computer Science and Digital FuturesKTH Royal Institute of TechnologyStockholm 10044Sweden Shenyang Institute of Automation(SIA) Chinese Academy of SciencesShenyang 110169China School of Mathematics Frontiers Science Center for Mobile Information Communication and SecuritySoutheast UniversityNanjing 211189China Purple Mountain Laboratories Nanjing 211111China AVIC Chengdu Aircraft Industrial(Group)Co. Ltd.Chengdu 610091China

Traditional machine learning relies on a centralized data pipeline for model training in various applications;however,data are inherently *** a decentralized nature of databases presents the serious challenge for collaboration:sending all decentralized datasets to a central server raises serious privacy *** there has been a joint effort in tackling such a critical issue by proposing privacy-preserving machine learning frameworks,such as federated learning,most state-of-the-art frameworks are built still in a centralized way,in which a central client is needed for collecting and distributing model information(instead of data itself)from every other client,leading to high communication burden and high vulnerability when there exists a failure at or an attack on the central *** we propose a principled decentralized federated learning algorithm(DeceFL),which does not require a central client and relies only on local information transmission between clients and their neighbors,representing a fully decentralized learning *** has been further proven that every client reaches the global minimum with zero performance gap and achieves the same convergence rate O(1=T)(where T is the number of iterations in gradient descent)as centralized federated learning when the loss function is smooth and strongly ***,the proposed algorithm has been applied to a number of applications to illustrate its effectiveness for both convex and nonconvex loss functions,time-invariant and time-varying topologies,as well as IID and Non-IID of datasets,demonstrating its applicability to a wide range of real-world medical and industrial applications.

关键词： decentralized federated learning smart manufacturing control systems privacy

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Lidar-Based Multiple Object Tracking with Occlusion Handling

Lidar-Based Multiple Object Tracking with Occlusion Handling

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IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

作者： Ruo-Tsz Ho Chieh-Chih Wang Wen-Chieh Lin Institute of Electrical and Control Engineering National Yang Ming Chiao Tung University Hsinchu Taiwan Department of Electronics and Electrical Engineering National Yang Ming Chiao Tung University Mechanical and Mechatronics Systems Research Laboratories Industrial Technology Research Institute Hsinchu Taiwan Department of Computer Science National Yang Ming Chiao Tung University Hsinchu Taiwan

Occlusion remains an issue in multiple object tracking, which could cause ambiguity in object detection, such as incorrect or missing detection. Under occlusion, a track could experience an early termination, resulting in identity switches and/or fragmentation. To recover from different lengths of occlusions, the track should be maintained by considering its occlusion status. To address the issues mentioned above, we propose an indicator that can model the track's occlusion extent via geometric information provided by LiDAR data. Through incorporating the indicator into the track management and data association process, it is feasible to prevent tracks from premature termination. The proposed method is evaluated on the collected dataset which undergoes frequent and severe occlusions. Compared to the state-of-the-art probabilistic tracking approach, our approach achieves improvements of 3.26% in MOTA and 5.36% in IDF1. Additionally, we obtain 9.89% improvements in IDF1 specifically for objects experiencing severe occlusions.

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Multi-Functional RIS Integrated Sensing and Communications for 6G Networks

arXiv

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arXiv 2024年

作者： Han, Dongsheng Wang, Peng Ni, Wanli Wang, Wen Zheng, Ailing Niyato, Dusit Al-Dhahir, Naofal The School of Electrical and Electronic Engineering North China Electric Power University Beijing102206 China Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power University Baoding071003 China The Department of Electronic Engineering Tsinghua University Beijing100084 China The Pervasive Communications Center Purple Mountain Laboratories Nanjing211111 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China The School of Computer Science and Engineering Nanyang Technological University 639798 Singapore The Department of Electrical and Computer Engineering The University of Texas Dallas United States

In this paper, we propose a novel multi-functional reconfigurable intelligent surface (MF-RIS) that supports signal reflection, refraction, amplification, and target sensing simultaneously. Our MF-RIS aims to enhance integrated communication and sensing (ISAC) systems, particularly in multi-user and multi-target scenarios. Equipped with reflection and refraction components (i.e., amplifiers and phase shifters), MF-RIS is able to adjust the amplitude and phase shift of both communication and sensing signals on demand. Additionally, with the assistance of sensing elements, MF-RIS is capable of capturing the echo signals from multiple targets, thereby mitigating the signal attenuation typically associated with multi-hop links. We propose a MF-RIS-enabled multi-user and multi-target ISAC system, and formulate an optimization problem to maximize the signal-to-interference-plus-noise ratio (SINR) of sensing targets. This problem involves jointly optimizing the transmit beamforming and MF-RIS configurations, subject to constraints on the communication rate, total power budget, and MF-RIS coefficients. We decompose the formulated non-convex problem into three sub-problems, and then solve them via an efficient iterative algorithm. Simulation results demonstrate that: 1) The performance of MF-RIS varies under different operating protocols, and energy splitting (ES) exhibits the best performance in the considered MF-RIS-enabled multi-user multi-target ISAC system;2) Under the same total power budget, the proposed MF-RIS with ES protocol attains 52.2%, 73.5%, and 60.86% sensing SINR gains over active RIS, passive RIS, and simultaneously transmitting and reflecting RIS (STAR-RIS), respectively;3) The number of sensing elements will no longer improve sensing performance after exceeding a certain number. © 2024, CC BY.

关键词： Budget control

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Spin wave eigenmodes in nanoscale magnetic tunnel junctions with perpendicular magnetic anisotropy

arXiv

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arXiv 2025年

作者： Meo, Andrea Sha, Chengcen Darwin, Emily Tomasello, Riccardo Carpentieri, Mario Krivorotov, Ilya N. Finocchio, Giovanni Department of Electrical and Information Engineering Politecnico di Bari BariI-70125 Italy Department of Physics and Astronomy University of California IrvineCA92697 United States Empa Swiss Federal Laboratories for Materials Science and Technology DübendorfCH-8600 Switzerland Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina MessinaI-98166 Italy

Magnetic tunnel junctions (MTJs) are key enablers of spintronic technologies used in a variety of applications including information storage, microwave generation and detection, as well as unconventional computing. Here, we present experimental and theoretical studies of quantized spin wave eigenmodes in perpendicular MTJs focusing on a coupled magnetization dynamics in the free (FL) and reference (RL) layers of the MTJ, where the RL is a synthetic antiferromagnet (SAF). Spin-torque ferromagnetic resonance (ST-FMR) measurements reveal excitation of two spin wave eigenmodes in response to applied microwave current. These modes show opposite frequency shifts as a function of out-of-plane magnetic field. Our micromagnetic simulations accurately reproduce the dependence of the mode frequencies on magnetic field and reveal the spatial profiles of the excitations in the FL and RL. The FL and RL modes generate rectified voltage signals of opposite polarity, which makes this device a promising candidate for a tunable dual-frequency microwave signal detector. The simulations show that weak interlayer exchange coupling within the SAF enhances the mode amplitudes. We also calculate the response of the detector as a function of in-plane magnetic field bias and find that its sensitivity significantly increases with increasing field. We experimentally confirm this prediction via ST-FMR measurements as a function of in-plane magnetic field. Our results provide deeper understanding of quantized spin wave eigenmodes in nanoscale MTJs with perpendicular magnetic anisotropy and demonstrate the potential of these devices for frequency-selective dual-channel microwave signal detectors. © 2025, CC BY.

关键词： Spin waves

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