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Symmetry-based phenomenological model for magnon transport in a multiferroic

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arXiv 2024年

作者： Harris, Isaac A. Husain, Sajid Meisenheimer, Peter Ramesh, Maya Park, Hyeon Woo Caretta, Lucas Schlom, Darrell Yao, Zhi Martin, Lane W. Íñiguez-González, Jorge Kim, Se Kwon Ramesh, Ramamoorthy Department of Physics University of California BerkeleyCA United States Materials Science Division Lawrence Berkeley National Laboratory BerkeleyCA United States Department of Materials Science and Engineering University of California BerkeleyCA United States Department of Materials Science and Engineering Cornell University Ithaca United States Department of Physics Korea Advanced Institute of Science and Technology Daejon Korea Republic of School of Engineering Brown University ProvidenceRI United States Applied Mathematics and Computational Research Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Materials Science and NanoEngineering Rice University HoustonTX United States Department of Physics and Astronomy Rice University HoustonTX United States Department of Chemistry Rice University HoustonTX United States Rice Advanced Materials Institute Rice University HoustonTX United States Materials Research and Technology Department Luxembourg Institute of Science and Technology Esch-Sur-Alzette Luxembourg Department of Physics and Materials Science University of Luxembourg Belvaux Luxembourg

Magnons – carriers of spin information – can be controlled by electric fields in the multiferroic BiFeO3 (BFO), a milestone that brings magnons closer to application in future devices. The origin of magnon-spin currents in BFO, however, is not fully understood due to BFO’s complicated magnetic texture. In this letter, we present a phenomenological model to elucidate the existence of magnon spin currents in generalized multiferroics by examining the symmetries inherent to their magnetic and polar structures. This model is grounded in experimental data obtained from BFO and its derivatives, which informs the symmetry operations and resultant magnon behavior. By doing so, we address the issue of symmetry-allowed, switchable magnon spin transport in multiferroics, thereby establishing a critical framework for comprehending magnon transport within complex magnetic textures. © 2024, CC BY.

关键词： Spin waves

Photoresponse of Thermally Evaporated Copper Oxide-Based Solar Cells 1

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Photoresponse of Thermally Evaporated Copper Oxide-Based Sol...

1st Middle East and North Africa Solar Conference, MENA-SC 2023

作者： Alami, Abdul Hai Ayoub, Mohamad Alashkar, Adnan Alasad, Shamma Mdallal, Ayman Khuri, Siren Aljaghoub, Haya University of Sharjah Sustainable Energy & Power Systems Research Centre Sustainable and Renewable Energy Engineering Department Sharjah United Arab Emirates American University of Sharjah Materials Science and Engineering PhD Program Sharjah United Arab Emirates American University of Sharjah Mechancial Engineering Department Sharjah United Arab Emirates University of Sharjah Sustainable Energy & Power Systems Research Centre Sharjah United Arab Emirates University of Sharjah Industrial Engineering and Engineering Management Department Sharjah United Arab Emirates

ISBN: (纸本)9781665491464

This study reports on the fabrication and characterization of a copper oxide (CuO)-based photoactive cell. Copper was thermally evaporated onto two substrates and post-treated using chemical and thermal treatments to obtain different semiconducting types of CuO. Absorption measurements were conducted to obtain the bandgaps of CuO, which were found to be 1.51 eV and 1.21 eV, for the chemically and thermally treated CuO, respectively. Finally, a chronoamperometry test was conducted to confirm the photoresponse of the cell, which showed a doubling of output current values under light conditions compared to dark conditions. © 2023 IEEE.

关键词： Copper oxides

Optoelectric Raman Nanosensors: Overcoming Intrinsic Limit in Nano-biosensing

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Research Square

Research Square 2024年

作者： Lian, Bin Li, Huaizhi Guo, Jianhe Fan, Donglei Emma Materials Science and Engineering Program Texas Materials Institute The University of Texas AustinTX78712 United States Walker Department of Mechanical Engineering Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Chandra Family Department of Electrical and Computer Engineering The University of Texas at Austin AustinTX78712 United States

It is intrinsically difficult to detect low-concentration biomolecules with both ultra-sensitivity and high speed for early-stage disease diagnosis. The challenge originates from the small size of nanosensors, which enables ultra-sensitivity biosensing, while also substantially increases the detection time of dilute molecules. in this work, we report an original optoelectric sensing scheme, along with an innovative device design and a strategic fabrication approach to overcome such a challenge in biosensing. The proposed scheme exploits the profound optoelectric effect of semiconductor silicon nanowires, which can readily enrich trace-amounts of biomolecules at the point of laser and simultaneously detect Raman signals of focused molecules. The device design includes large arrays of silicon nanorods with electrodes integrated at their roots, and surface-distributed dense plasmonic silver nanoparticles for surface-enhanced Raman spectroscopy (SERS) detection. Operating at only -0.8 V in an electrochemical cell, these optoelectric nanosensors readily achieve a 150-fold signal enhancement, improving the detection limit of probing molecules, adenine, by five orders of magnitude, to 0.6 fM. The enhancement effect is robust, observed across concentrations from 1 μM to 1 fM. The working mechanism is general, not only for detecting small molecules, such as adenine, but also for large charged molecules, such as Vertebrate DNA. The underlying novel mechanism is unraveled by multiscale numerical simulations and calculations. This research, addressing an arduous bottleneck issues in nanobiosensing, is expected to inspire a new class of biochemical sensors, important for the practical detection of trace-amount biochemicals in solution, important for clinic relevant early-stage disease diagnostics. © 2024, CC BY.

关键词： Nanorods

Co Metal ALD on Cu with Cyclic Clean by Peroxide and Hydrazine for Inverse Hybrid Metal Bonding

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Co Metal ALD on Cu with Cyclic Clean by Peroxide and Hydrazi...

Technology, Systems and Applications (VLSI-TSA/VLSI-DAT), International VLSI Symposium on

作者： Cheng-Hsuan Kuo Dipayan Pal Victor Wang Madison Manley Rohan Sahay Ravindra Kanjolia Mansour Moinpour Jacob Woodruff Bakir Muhannad Jeff Spiegelman Andrew C. Kummel Materials Science and Engineering Program University of California San Diego Department of Chemistry and Biochemistry University of California San Diego Georgia Institute of Technology EMD Electronics Rasirc

ISBN: (数字)9798350360349

ISBN: (纸本)9798350360356

To meet the demands of data-intensive applications such as artificial intelligence (AI) and high-performance computing (HPC), there is a need for tighter integration to minimize electrical interconnect delays and energy [1] . Typical I/O pitches for μ-bumps range from hundreds of microns to $\sim 50\mu \mathrm{m}$ for conventional flip chip bonding therefore limiting the number of I/O's. When scaling down solder-based μ-bumps, adjacent interconnects could be shorted during the bonding process. As a result, the investigation of new bonding techniques has become more and more popular. The feasibility of a 3D bonding technology for ultra-dense input/output (I/O) interconnects using cobalt selective atomic layer deposition (Co ALD) was explored with a preliminary testbed [2] .

关键词： Micrometers Three-dimensional displays Limiting High performance computing Very large scale integration Delays Flip-chip devices

Bone quality in zebrafish vertebrae improves after alendronate administration in a glucocorticoid-induced osteoporosis model

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Journal of the Mechanical Behavior of Biomedical materials 2024年 154卷 106521页

作者： Bohns, Fabio Rocha Akhtar, Riaz Chuang, Yung-Jen Chen, Po-Yu Department of Materials Science and Engineering National Tsing Hua University Hsinchu Taiwan Department of Mechanical Materials and Aerospace Engineering University of Liverpool Liverpool United Kingdom International Intercollegiate Ph.D. Program National Tsing Hua University Hsinchu Taiwan School of Medicine National Tsing Hua University Hsinchu Taiwan

Glucocorticoid-induced osteoporosis (GIOP) changes the microarchitecture of bones and often leads to the reduction of bone-mineral density (BMD) and increased fracture rates. Zebrafish has been used as an alternative model for GIOP, however, the interaction of GIOP, and its treatment, with zebrafish bone morphometrics and mechanical properties, remains a challenge. Thus, this study aimed to evaluate the effects of prednisolone and alendronate on the properties of zebrafish vertebrae. Adult 7-month-old zebrafish were distributed into four groups: control (CTRL), prednisolone-only (PN), alendronate-only (ALN), and the sequential use of both medicines (PN + ALN). Fish skeletons were scanned via micro-tomography (n = 3) to obtain vertebra morphometrics (e.g., BMD). Bone morphology was assessed using scanning electron microscopy (n = 4) and the biomechanical behaviour with nanoindentation technique (n = 3). The BMD decreased in PN (426.08 ± 18.58 mg/cm3) and ALN (398.23 ± 10.20 mg/cm3) groups compared to the CTRL (490.43 ± 41.96 mg/cm3) (p 3) (p > 0.05). The bone layered structures remain preserved in all groups. The vertebrae of the groups that received ALN and PN + ALN, displayed higher modulus of elasticity (27.27 ± 1.59 GPa and 25.68 ± 2.07 GPa, respectively) than the CTRL (22.74 ± 1.60 GP) (p © 2024 Elsevier Ltd

关键词： Bone

A new type of compositionally complex M5Si3 silicides: Cation ordering and unexpected phase stability

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arXiv 2021年

作者： Shivakumar, Sashank Qin, Mingde Zhang, Dawei Hu, Chongze Yan, Qizhang Luo, Jian Department of NanoEngineering Program of Materials Science and Engineering University of California San Diego La Jolla CA92093 United States

A new type of compositionally complex (medium- or high-entropy) M5Si3 silicides is synthesized. Both (V1/5Cr1/5Nb1/5Ta1/5W1/5)5Si3 and (Ti1/5Zr1/5Nb1/5Mo1/5Hf1/5)5Si3 form single-phase homogenous solid solutions. Notably, (V1/5Cr1/5Nb1/5Ta1/5W1/5)5Si3 forms the hexagonal γ (D88) phase, while all its five constituent binary silicides, V5Si3, Cr5Si3, Nb5Si3, Ta5Si3, and W5Si3, are stable in the tetragonal α (D8l) or β (D8m) phases. Annealing at 1600oC demonstrates that this hexagonal γ phase is stable. Comparison of the experimental and calculated X-ray diffraction patterns, Rietveld refinements, and analysis of aberration-corrected scanning transmission electron microscopy high-angle annular dark-field images suggest cation ordering, which reduces the configurational entropy. This work expands the field of high-entropy and compositional complex ceramics by not only discovering a new compositional complex silicide phase but also demonstrating the cation ordering and unusual phase stability. These compositionally complex silicides can be combined with refractory high-entropy alloys to make the high-entropy counterparts to the Nb-silicide and Mo-Si-B composites. © 2021, CC BY.

关键词： Entropy

The modulating effect of N coordination on single-atom catalysts researched by Pt-N_(x)-C model through both experimental study and DFT simulation

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Journal of materials science & Technology 2021年第32期91卷 160-167页

作者： Mengmeng Fan Jiewu Cui Junjie Zhang Jingjie Wu Shuangming Chen Li Song Zixing Wang Ao Wang Robert Vajtai Yucheng Wu Pulickel MAjayan Jianchun Jiang Dongping Sun Nanjing Forestry University Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest ResourcesCollege of Chemical EngineeringNanjing 210037China Rice University Department of Materials Science and NanoEngineeringHoustonTX 77005USA Hefei University of Technology School of Materials Science and EngineeringHefei 230009China University of Cincinnati Department of Chemical and Environmental EngineeringCincinnatiOH 45221USA University of Science and Technology of China National Synchrotron Radiation LaboratoryCAS Center for Excellence in NanoscienceHefei 230026China Nanjing University of Science and Technology Chemicobiology and Functional Materials InstituteNanjing 210094China Key Lab of Biomass Energy and Material Jiangsu ProvinceJiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesInstitute of Chemical Industry of Forest ProductsChinese Academy of ForestryNanjing 210042China

N-doped carbon-based single-atom catalysts(NC-SACs) are widely researched in various electrochemical reactions due to high metal atom utilization and catalytic *** catalytic activity of NC-SACs originates from the coordinating structure between single metal site(M) and the doped nitrogen(N) in carbon matrix by forming M-N_(x)-C structure(1≤x≤4).The M-N4-C structure is widely considered to be the most stable and effective catalytic ***,there is no in-depth research for the "x" modulation in Pt-Nx-C structure and the corresponding catalytic ***,atomically dispersed Pt on N-doped carbon(Pt-NC) with Pt-Nx-C structure(1≤x≤4),as a research model,is fabricated by a ZIF-8 template and applied to catalytic oxygen *** carbonization temperatures are used to control N loss,and then modulate the N coordination of Pt-Nx-C *** Pt-NC has the predictable low half-wave potential(E_(1/2)) of 0.72 V vs RHE compared to the Pt/C 20% of 0.81 V due to low Pt ***,the Pt-NC shows a high onset potential(1.10 V vs RHE,determined for j=-0.1 mA cm^(2)) and a high current density of 5.2 mA cm^(-2),more positive and higher than that of Pt/C 20%(0.96 V) and 4.9 mA cm^(-2),*** the structural characterization and DFT simulation confirmed,the reducing PtN coordination number induces low valence of Pt atoms and low free energy of oxygen reduction,which is responsible for the improved catalytic ***,the Pt-NC shows high mass activity(172 times higher than that of Pt/C 20%),better stability and methanol crossover resistance.

关键词： Modulating effect N coordination Single-atom catalysts Pt-N_(x)-C model DFT simulation

Perspective on descriptors of mechanical behavior of cubic transition-metal carbides and nitrides

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arXiv 2024年

作者： Kindlund, Hanna Ciobanu, Theodora Kodambaka, Suneel Ciobanu, Cristian V. Department of Materials Science and Engineering Virginia Polytechnic Institute State University BlacksburgVA24061 United States University of Notre Dame College of Arts and Letters Notre DameIN46556 United States Department of Mechanical Engineering and Materials Science Program Colorado School of Mines GoldenCO80401 United States

Cubic rocksalt structured transition-metal carbides, nitrides (TMC/Ns), and related alloys, are attractive for a wide variety of applications, notably as hard, wear-resistant materials. To-date, valence electron concentration (VEC) is used as a good indicator of stability and mechanical properties of these refractory compounds. In this perspective, we argue for the need of electronic descriptors beyond VEC to explain and predict the mechanical behavior of the cubic TMC/Ns. As such, we point out that descriptors that highlight differences between constituents, along with semi-empirical models of mechanical properties, have been underused. Additionally, it appears promising to partition VEC into contribution to ionic, covalent, and metallic bonds and we suggest that such partition could provide more insights into predicting mechanical properties in the future. Copyright © 2024, The Authors. All rights reserved.

关键词： Nitrides

Exploring Nanoscale Photoresponse Mechanisms for Enhanced Photothermoelectric Effects in van der Waals Interfaces

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arXiv 2024年

作者： Xu, Da Liu, Qiushi Liang, Boqun Yu, Ning Ma, Xuezhi Xu, Yaodong Taniguchi, Takashi Lake, Roger K. Yan, Ruoxue Liu, Ming Department of Electrical and Computer Engineering University of California - Riverside RiversideCA92521 United States Department of Chemical and Environmental Engineering University of California - Riverside RiversideCA92521 United States International Center for Materials Nanoarchitectonics National Institute for Materials Science Ibaraki Tsukuba305-0044 Japan Materials Science and Engineering Program University of California - Riverside RiversideCA92521 United States

Integrated photodetectors are crucial for their high speed, sensitivity, and efficient power consumption. In these devices, photocurrent generation is primarily attributed to the photovoltaic (PV) effect, driven by electron-hole separations, and the photothermoelectric (PTE) effect, which results from temperature gradients via the Seebeck effect. As devices shrink, the overlap of these mechanisms—both dependent on the Fermi level and band structure—complicates their separate evaluation at the nanoscale. This study introduces a novel 3D photocurrent nano-imaging technique specifically designed to distinctly map these mechanisms in a Schottky barrier photodiode featuring a molybdenum disulfide and gold (MoS2-Au) interface. We uncover a significant PTE-dominated region extending several hundred nanometers from the electrode edge, a characteristic facilitated by the weak electrostatic forces typical in 2D materials. Unexpectedly, we find that incorporating hexagonal boron nitride (h-BN), known for its high thermal conductivity, markedly enhances the PTE response. This counterintuitive enhancement stems from an optimal overlap between thermal and Seebeck profiles, presenting a new pathway to boost device performance. Our findings highlight the capability of this imaging technique to not only advance optoelectronic applications but also to deepen our understanding of light-matter interactions within low-dimensional systems. © 2024, CC BY.

关键词： Van der Waals forces