Materials Today Physics最新文献_第4页

Ballistic transport from propagating vibrational modes in amorphous silicon dioxide: Thermal experiments and atomistic-machine learning modeling

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2025.101659

Man Li , Lingyun Dai , Huan Wu , Yan Yan , Joon Sang Kang , Sophia King , Patricia E. McNeil , Danielle Butts , Tiphaine Galy , Michal Marszewski , Esther Lan , Bruce S. Dunn , Sarah H. Tolbert , Laurent Pilon , Yongjie Hu

Understanding thermal transport in amorphous materials is critical for a wide range of applications, including buildings, vehicles, aerospace, and acoustic technologies. Despite its importance, the fundamental behavior of heat carriers in amorphous structures remains poorly understood and is often attributed to localized vibrational modes with mean free paths of about 1 nm, posing significant challenges for engineering their thermal functionalities. In this study, we present experimental measurements on mesoporous silica and atomistic analyses using Monte Carlo simulations and machine learning models to quantify the relationship between nanoarchitecture and effective thermal conductivity. Through rational chemical synthesis and ultrafast spectroscopy measurements, a strong size dependence within the sub-10 nm regime is observed, where the classical Fourier heat conduction theory fails to account for the effects of porosity and pore size. This deviation from diffusive transport is attributed to the significant contribution of propagating vibrational modes, in addition to non-propagating modes, revealing unexpectedly long mean free paths and ballistic thermal transport for heat carriers in amorphous silica. The fundamental vibrational modes in amorphous silica are further investigated using spectral-dependent Boltzmann transport equation simulations and molecular dynamics with machine learning potentials, showing good agreement with experimental results. This study provides valuable insights into nanoscale-modulated thermal transport properties in mesoporous silica and opens new opportunities for the rational design of thermally insulating materials.

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引用次数: 0

Textured elastomeric interface actuated sustainable and bacteriostatic sensors for wearable electronics in healthcare 用于医疗保健中可穿戴电子设备的可持续性和抑菌传感器的纹理弹性界面

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2025.101648

Rui Zhu , Jingqi Wu , Fei Li , Siqi Nan , Fenglong Shang , Jie Zhang

Flexible pressure sensors are highly demanded to digitize physical and biological signals for therapeutic and healthcare analyses, yet facing significant challenges for long-term wearability due to bacterial adhesion that compromises the data stability in addition to hygiene concerns. To date, few studies address the impact of bacterial adhesion on sensor performance, durability, and lifespan under prolonged wearing conditions. Herein, we investigate the performance stability of wearable flexible sensors under prone bacterial growth environment, where micro-nano elastomeric interface, designed to enhance sensing performance effectively inhibit bacterial adhesion and resist biofilm formation. The antibacterial mechanisms are through created interfacial energy gradients by nano-pillar structures and disabled bacterial interaction by micron-scale interwoven structures to block signaling paths through parallel concave lines. The adhesion rates of Escherichia coli and Staphylococcus aureus can be reduced by over 90 %, resulting less than 2.69 % sensing signal variation, which substantially mitigate the detrimental effects of biofouling on pulsatile waveform detection when wearing. The resulted wearable sensor ensures reliable healthcare monitoring continuously through the day. This study unravel sensor design strategy by incorporating tailored micro-nanostructured elastomeric sensing film to ensure pressure sensor performance yet enhanced sensor's hygiene effectiveness for wearability and longivity.

柔性压力传感器是高度要求数字化的物理和生物信号的治疗和医疗保健分析，但面临重大…

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引用次数: 0

Uniaxial zero thermal expansion in low-cost Mn2OBO3 from 3.5 to 1250 K 低成本Mn2OBO3的单轴零热膨胀从3.5到1250 K

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2025.101650

Chi-Hung Lee, Cheng-Yen Lin, Guan-Yu Chen

Unique zero thermal expansion (ZTE) materials are valuable for use in precision instruments, including electronics, aerospace parts, and engines. However, most ZTE materials have a temperature range less than 1000 K under which they do not expand. In this study, we present a uniaxial ZTE in the low-cost Mn₂OBO₃ with a thermal expansion coefficient of −4(1) × 10⁻⁷ K⁻¹ along the X₁ principal axis from 3.5 to 1250 K. The monoclinic structure of Mn₂OBO₃ remains stable over the entire temperature range in ambient conditions. Considerable thermal contraction on the BO₃ trigonal planar and thermal expansion on the MnO₆ octahedra combine to produce uniaxial ZTE. Temperature-dependent Raman scattering reveals anharmonic low-frequency modes associated with MnO₆ Rigid Unit Modes (RUMs), which likely play a critical role in driving thermal contraction in the BO₃ trigonal planar. No charge order-disorder transition, which could cause thermal contraction, was observed up to 1250 K.

独特的零热膨胀（中兴）材料在精密仪器中有价值，包括电子，航空航天零件和发动机。然而，大多数中兴材料的温度范围小于1000k，在此温度范围内它们不会膨胀。在这项研究中，我们在低成本的Mn2OBO3中提出了一个单轴中兴通讯，沿着X1主轴从3.5到1250 K的热膨胀系数为-4(1)×10-7 K-1。在室温条件下，Mn2OBO3的单斜晶型结构在整个温度范围内保持稳定。BO3三角形平面上的大量热收缩和MnO6八面体上的热膨胀共同产生单轴中兴。温度相关的拉曼散射揭示了与MnO6刚性单元模式（RUMs）相关的非谐波低频模式，这些模式可能在驱动BO3三角形平面的热收缩中起关键作用。在1250k温度下，未观察到引起热收缩的有序-无序转变。

引用次数: 0

Energy band structure perturbation induced deviation on precise ultrafast laser nano-structuring 精密超快激光纳米结构的能带结构微扰诱发偏差

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2024.101636

Zhenyuan Lin , Lingfei Ji , Bohao Zhou , Weigao Sun , Dengcai Yang , Feng Yang , Tianran Yao

The effect of the material lattice structure during the laser nano-structuring is generally overlooked. Here, we reveal the energy band structure perturbation at different polarizations, and its underlying mechanism functioning on the ultrafast laser nano-structuring. This phenomenon is confirmed by the variation in deviation of femtosecond laser-induced periodic surface structures (LIPSS) orientation on thin-film lithium niobate (LiNbO₃). An increase in the laser fluence leads to a notable enlarging in the effective bandgap of LiNbO₃ from 3.78 to 5.70 eV, weakening the impact of polarization-dependent intrinsic perturbations within LiNbO₃ that contribute to the deviation of LIPSS orientation. Precise writing of polarization dependent structures and selective reading of corresponding information are realized via directional modulation of LIPSS. The study of energy band structure perturbation effect develops a novel mechanism for the deviation angle modulation of nano-structuring at the accuracy compensation within 1°, thus promising enhanced precision for future laser nano-structuring applied in advanced nano-optics devices.

在激光纳米结构中，材料晶格结构的影响通常被忽视。在此，我们揭示了不同极化下的能带结构摄动及其在超快激光纳米结构中的作用机制。这一现象被飞秒激光诱导的周期性表面结构（LIPSS）在薄膜铌酸锂（LiNbO3）上的取向偏差变化所证实。激光能量的增加导致LiNbO3的有效带隙从3.78 eV增加到5.70 eV，减弱了LiNbO3内部极化相关的本征微扰对LIPSS取向偏差的影响。通过对LIPSS的定向调制，实现了极化相关结构的精确写入和相应信息的选择性读取。通过对能带结构摄动效应的研究，提出了一种精度补偿在1°以内的纳米结构偏差角调制机制，为未来激光纳米结构在先进纳米光学器件中的应用提供了更高的精度。

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引用次数: 0

Microscopic mechanism and applications of radiative cooling materials: A comprehensive review 辐射冷却材料的微观机理及其应用综述

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2024.101643

Kai Zhang, Bingyang Wu

This paper presents a state-of-the-art review on the microscopic mechanisms of existing radiative cooling materials. In this review, we analyze the microscopic mechanisms of efficient mid-infrared emissivity generated by photonic crystal-based radiative coolers, polymer-based radiative coolers, polar dielectric particle-polymer-based radiative coolers, and adaptive radiative coolers after clarifying the basic physical concepts of radiative cooling. Then, the mid-infrared emissivity and associated cooling properties of different materials, advantages and disadvantages of different radiative coolers and their application scenarios are discussed in detail. Finally, the threshold of spectral modulation is derived to address the relationship between mid-infrared emissivity and solar reflectance to achieve radiative cooling. This review can provide guidance for the design and application of radiative coolers.

本文对现有辐射冷却材料的微观机理进行了综述。本文在阐明辐射冷却的基本物理概念的基础上，分析了光子晶体辐射冷却器、聚合物辐射冷却器、极性介电粒子-聚合物辐射冷却器和自适应辐射冷却器产生高效中红外发射率的微观机理。然后，详细讨论了不同材料的中红外发射率和相关冷却性能、不同辐射冷却器的优缺点及其应用场景。最后，推导了光谱调制的阈值，以解决中红外发射率与太阳反射率之间的关系，从而实现辐射冷却。本文综述可为辐射冷却器的设计和应用提供指导。

引用次数: 0

Magneto-transport properties of NiCoCrFePd high entropy alloy films NiCoCrFePd高熵合金薄膜的磁输运特性

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2024.101644

Abid Hussain , S.A. Khan , Anju Kumari , R.C. Meena , Sanjay K. Kedia , Deeksha Khandelwal , P.K. Kulriya

This study aims to develop for the first time thin films of NiCoCrFePd high entropy alloy (HEA) to investigate the structural, magnetic, and transport properties for potential room temperature spin gapless semiconducting (SGS) applications. The as grown films were subjected to different annealing temperatures ranging from 400 °C to 600 °C to investigate the role of thermal generation of charge carriers and its effect on the (SGS) properties. The temperature dependent X-ray diffraction unveils structural stability down to 30 K with no phase transformations, however improvement in the crystallinity was observed with the increase in the annealing temperature. Rutherford backscattering spectroscopy shows depth dependent uniformity in the elemental distribution. Additionally, the magneto-transport studies revealed ferromagnetic behavior with a magnetic saturation values ranging from 165 emu/cm³ to 375 emu/cm³ and the Curie temperatures in the range of 263 K to 507 K. Further, the resistivity measurements confirmed a semiconducting behavior, with negative magnetoresistance corresponding to all the annealed samples. A two-channel conduction mechanism is used to explain the transport behaviour with one gapless and another gapped channel with activation energies ranging from 216.47 ± 3.63 meV to 86.85 ± 0.93 meV for different annealed samples. The observation of small anomalous Hall conductivity ranging from 25.2 Scm⁻¹ to 66.7 Scm⁻¹ and vanishing thermoelectric power lying in the range 3.11 μV/K to 4.11 μV/K confirms the SGS behavior with hole-dominant charge carriers. Thus, evidently the annealing temperature can be used to tune the spin transport properties by altering energy band gaps and density of states near the Fermi energy (

ε_{F}

).

本研究旨在首次开发NiCoCrFePd高熵合金（HEA）薄膜，以研究其结构、磁性和输运性质，用于潜在的室温自旋无间隙半导体（SGS）应用。在400 ~ 600℃的不同退火温度下，研究热生成载流子的作用及其对（SGS）性能的影响。温度相关的x射线衍射揭示了低至30k的结构稳定性，没有相变，但结晶度随着退火温度的升高而改善。卢瑟福后向散射光谱显示出元素分布随深度的均匀性。此外，磁输运研究表明，磁饱和值在165 ~ 375 emu/cm3之间，居里温度在263 ~ 507 K之间。此外，电阻率测量证实了半导体行为，与所有退火样品对应的负磁电阻。采用双通道传导机制解释了不同退火样品在216.47±3.63 meV至86.85±0.93 meV之间的无间隙通道和有间隙通道的输运行为。观察到微小的异常霍尔电导率（25.2 ~ 66.7 cm-1）和消失热电功率（3.11 ~ 4.11 μV/K），证实了空穴优势载流子的SGS行为。因此，显然退火温度可以通过改变能带间隙和费米能（）附近的态密度来调节自旋输运性质。

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引用次数: 0

Symmetry breaking and structural phase transition in frustrated quantum kagome antiferromagnet barlowite via pressure tuning strategy 基于压力调谐策略的受挫量子Kagome反铁磁石的对称破缺和结构相变

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2025.101645

Yaxiao Luo, Hong Yu, Liangyu Wang, Pengfei Xu, Xuhong Xing, Xu Wang, Jian Zhang, Yanmei Ma

As promising members of the two-dimensional kagome lattice materials, the copper-based compounds of the atacamite family have attracted much attention due to their unique structures and abundant properties. In this work, research efforts were focused on exploring the structural, optical and magnetic properties, as well as the compression behavior, of barlowite, Cu₄(OH)₆FBr, which possesses a geometrically perfect kagome lattice of Cu²⁺ cations. The powder samples of barlowite were synthesized via a hydrothermal strategy. They exhibited a canted antiferromagnetic behavior below 15 K, above which a magnetic transition to paramagnetism was observed. The high pressure experimental technique was employed to investigate the structural evolution of barlowite samples. The observed stepwise structural transformation from the initial hexagonal to the intermediate orthorhombic and the eventual monoclinic phase, is correlated with a continuous variation of the interlayer Cu occupation, the halide sizes, and the distortion of the kagome lattice within the system under pressure. The phase transition mechanism was also closely related with the combined contributions of an increase in external pressure and the cooperative intrinsic Jahn-Teller distortion. These findings advance the understanding of pressure-induced structural evolution and lattice deformation in barlowite and could be applied to other copper-based quantum kagome antiferromagnet materials.

atacamite族铜基化合物作为二维kagome晶格材料中很有前途的成员，因其独特的结构和丰富的性能而备受关注。在这项工作中，研究工作集中在探索具有几何完美的Cu2+阳离子kagome晶格的钡钡石Cu4(OH)6FBr的结构，光学和磁性以及压缩行为。采用水热法制备了钡钡石粉末样品。它们在15k以下表现出倾斜的反铁磁行为，在15k以上观察到向顺磁性的磁跃迁。采用高压实验技术研究了沸石试样的结构演化过程。观察到的从最初的六方相到中间正交相和最终的单斜相的逐步结构转变与层间Cu占位、卤化物尺寸和系统内kagome晶格在压力下的畸变的连续变化有关。相变机制也与外部压力的增加和协同固有的Jahn-Teller畸变的共同作用密切相关。这些发现促进了对压力诱导的钡石结构演化和晶格变形的理解，并可应用于其他铜基量子kagome反铁磁体材料。

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引用次数: 0

Ce doping induces lattice expansion of cobalt oxide electrocatalyst to achieve efficient proton exchange membrane water electrolysis Ce掺杂诱导氧化钴电催化剂晶格膨胀实现高效质子交换膜电解

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-02-01 DOI: 10.1016/j.mtphys.2024.101641

Zhi Wang , Jinpeng Li , Chengdeng Wang , Jiashuai Wang , Xiangrui Chen , Jun Wu , Zhiming Bai , Yan Gao , Li Chen , Xiaoqin Yan

The development of non-precious metal anode catalysts with high performance and low cost for proton exchange membrane (PEM) water electrolysis presents a significant challenge. This work successfully synthesized a bimetallic-doped cobalt-based oxide titanium diboride composite structure catalyst (Ce-Mn-Co₃O₄/TiB₂) by combining hydrothermal methods with heat treatment processes. Ce doping induces surface oxygen vacancies of Co₃O₄ to optimize adsorption energy, while Mn stabilizes lattice oxygen and impedes the dissolution of metal ions. Theoretical simulations support the experimental results, highlighting the strain effect of Ce doping on the Co₃O₄-TiB₂ interface, promoting further charge redistribution, and enhancing catalyst conductivity. Ce-Mn-Co₃O₄/TiB₂ exhibits a low oxygen evolution overpotential (389 mV @10 mA/cm²). Upon assembly into a PEM electrolytic cell, it achieves a current density of 250 mA/cm² at 1.63 V and demonstrates stable operation for nearly 25 h. This research provides novel ideas and methodologies for developing non-precious metal OER electrocatalysts suitable for PEM electrolysis.

开发高性能、低成本的质子交换膜（PEM）电解用非贵金属阳极催化剂是一个重大挑战。本工作通过水热法与热处理工艺相结合成功合成了一种双金属掺杂钴基氧化物二硼化钛复合结构催化剂（Ce-Mn-Co3O4/TiB2）。Ce掺杂诱导Co3O4表面氧空位优化吸附能，Mn掺杂稳定晶格氧，阻碍金属离子的溶解。理论模拟支持实验结果，强调了Ce掺杂对Co3O4-TiB2界面的应变效应，促进了进一步的电荷再分配，提高了催化剂的导电性。Ce-Mn-Co3O4/TiB2具有低析氧过电位（389 mV @10mA/cm2）。在组装成PEM电解电池后，它在1.63 V下达到250 mA/cm2的电流密度，并表现出近25小时的稳定运行。本研究为开发适用于PEM电解的非贵金属OER电催化剂提供了新的思路和方法。

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引用次数: 0

Innovative dual-band energy-efficient smart windows using VO2(M)-Based Fabry-Pérot structures for solar and radiative cooling modulation

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-01-31 DOI: 10.1016/j.mtphys.2025.101665

Joonho Keum , Jun Choi , Sujin Kim , Guyoung Kang , Byuonghong Lee , Min Jae Lee , Woochul Kim

Thermochromic windows have been studied as a promising solution for energy-efficiency with the dynamical adjustment of solar heating in response to temperature. Recent advancements in the field have introduced simultaneous multiband modulation, incorporating radiative cooling in the longwave infrared range. In this work, we present VO₂(M)/TiO₂(A)/ITO multilayer-coated glass (referred to as VTI) as a scalable and effective smart window that modulates both solar transmission and radiative cooling concurrently. As a semitransparent window in the solar spectrum, the VTI coating achieves nearly 100 % visual clarity, 38.5 % visible transparency, and 8.5 % modulation of solar transmittance. In the longwave infrared region, the VTI multilayer demonstrates an exceptional broadband emissivity shift of up to 42.5 %, made possible by an innovative Fabry-Pérot (F-P) cavity composed of absorbing metal oxides. This high degree of emissivity modulation is maintained across a wide range of spacer thicknesses, from 100 to 500 nm, as confirmed by both experimental data and simulations. The modulation mechanism of the F-P cavity which use ultrathin spacer (λ/140 ∼ λ/16) at its resonant absorption range is explained through incremental phasor analysis by the transfer-matrix method. Additionally, the scalability and practicality of the VTI film are supported by its three-layer composition and the room-temperature reactive magnetron sputtering deposition process. These results suggest that the design principles presented here could inspire further innovations in broadband longwave infrared emissivity modulation, utilizing ultrathin F-P cavities composed of semitransparent metal oxides.

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引用次数: 0

Optimized pyramidal honeycomb PEEK/CF composites metastructure through 3D printing for broadband electromagnetic wave absorption 通过3D打印优化锥体蜂窝PEEK/CF复合材料元结构，用于宽带电磁波吸收

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-01-01 DOI: 10.1016/j.mtphys.2024.101620

Ximing Zhang , Guoke Wei , Xinghan Huang , Hang Zhang , Xingyu Hao , Shujuan Tan , Kui Liu , Guangbin Ji

This study presents a novel pyramidal honeycomb metastructure, which integrates the geometric advantages of honeycomb and pyramid designs to achieve highly effective electromagnetic wave (EMW) absorption with reduced thickness. The pyramidal honeycomb metastructure capitalizes on the angle insensitivity characteristics of pyramidal geometries while leveraging the weight reduction benefits inherent in honeycomb designs. This metastructure is fabricated using an additive manufacturing (AM) process, specifically employing PEEK/CF composite through the fused deposition modeling (FDM) method, followed by a spraying process. The dimensions of the pyramidal honeycomb metastructure were optimized using simulation process, and its EMW absorption mechanism was thoroughly analyzed. The effective absorption bandwidth (EAB) of the composite metastructure nearly spans the Ku, K, and Ka bands at thin thicknesses, maintaining high performance even at incidence angles up to 45°. This research provides a valuable approach for aerospace applications, expanding the potential of 3D printing technologies in multi-scenario EMW absorption.

本文提出了一种新型的金字塔蜂窝元结构，它结合了蜂窝和金字塔设计的几何优势，以减少厚度实现高效的电磁波吸收。锥体蜂窝元结构利用锥体几何形状的角度不敏感特性，同时利用蜂窝设计中固有的减轻重量的好处。该元结构是使用增材制造（AM）工艺制造的，特别是通过熔融沉积建模（FDM）方法使用PEEK/CF复合材料，然后进行喷涂工艺。采用仿真方法对锥体蜂窝元结构进行了尺寸优化，并对其吸收EMW的机理进行了深入分析。复合元结构的有效吸收带宽（EAB）在薄厚度下几乎跨越Ku， K和Ka波段，即使在入射角高达45°时也能保持高性能。这项研究为航空航天应用提供了一种有价值的方法，扩大了3D打印技术在多场景EMW吸收中的潜力。

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引用次数: 0