Deterministic spin–orbit torque (SOT) switching of perpendicular magnets without external magnetic fields remains a central challenge for scalable SOT-MRAM. Here, we demonstrate that dimensional engineering of a Co/W superlattice spin–orbit layer enables >90% field-free switching of perpendicular CoFeB. Harmonic Hall measurements reveal an unconventional out-of-plane torque, while first-principles calculations reveal reconstruction of the spin-resolved electronic structure and increased W-projected out-of-plane spin character, together supporting the modification of torque symmetry through Co/W superlattice engineering. The optimized superlattice achieves a critical current density of 23.3 MA cm–2 and a thermal stability factor Δ ≈ 45. Nanoscale devices (100 nm) preserve deterministic field-free reversal with comparable efficiency, confirming scalability toward magnetic tunnel junction integration. Micromagnetic analysis shows that out-of-plane spin-polarized torque together with canted anisotropy enables intrinsic symmetry breaking, highlighting superlattice engineering as a route to tailor torque symmetry for effective field-free SOT devices.
无外磁场的垂直磁体的确定性自旋-轨道转矩（SOT）切换仍然是可扩展SOT- mram的核心挑战。在这里，我们证明了Co/W超晶格自旋轨道层的尺寸工程使垂直CoFeB的>90%无场开关成为可能。谐波霍尔测量揭示了一个非常规的面外扭矩，第一性原理计算揭示了自旋分辨电子结构的重建和W-投影的面外自旋特征的增加，共同支持通过Co/W超晶格工程改变扭矩对称性。优化后的超晶格的临界电流密度为23.3 MA cm-2，热稳定系数Δ≈45。纳米器件（100纳米）以相当的效率保持确定性的无场反转，证实了磁隧道结集成的可扩展性。微磁分析表明，面外自旋极化扭矩加上倾斜的各向异性会导致固有的对称性破缺，这突出了超晶格工程是为有效的无场SOT器件量身定制扭矩对称性的途径。
{"title":"Dimensional Engineering of Co/W Superlattices Enables Out-of-Plane Spin Polarization with 90% Field-Free Switching in Perpendicular CoFeB","authors":"Yu-Lon Lin,Jing-Wen Chen,Yan-Zhen Huang,Tzu-Chuan Hsin,Chih-Wei Cheng,Yu-Han Huang,Ssu-Yen Huang,Shintaro Hara,Tatsuya Kishi,Yuan-Chieh Tseng","doi":"10.1021/acs.nanolett.6c04408","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c04408","url":null,"abstract":"Deterministic spin–orbit torque (SOT) switching of perpendicular magnets without external magnetic fields remains a central challenge for scalable SOT-MRAM. Here, we demonstrate that dimensional engineering of a Co/W superlattice spin–orbit layer enables >90% field-free switching of perpendicular CoFeB. Harmonic Hall measurements reveal an unconventional out-of-plane torque, while first-principles calculations reveal reconstruction of the spin-resolved electronic structure and increased W-projected out-of-plane spin character, together supporting the modification of torque symmetry through Co/W superlattice engineering. The optimized superlattice achieves a critical current density of 23.3 MA cm–2 and a thermal stability factor Δ ≈ 45. Nanoscale devices (100 nm) preserve deterministic field-free reversal with comparable efficiency, confirming scalability toward magnetic tunnel junction integration. Micromagnetic analysis shows that out-of-plane spin-polarized torque together with canted anisotropy enables intrinsic symmetry breaking, highlighting superlattice engineering as a route to tailor torque symmetry for effective field-free SOT devices.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"16 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-12DOI: 10.1021/acs.nanolett.6c04034
Kaichen Wang,Yu Zhou,Bori Shi,Xiaofei Sun,Xiao Qiu,Zhiyong Fan
Emerging low-dimensional chiral perovskites have recently demonstrated significant application potential in circularly polarized light detection, spintronics, and quantum information technology due to their unique chiroptical activity and spin-selective properties. This review systematically summarizes their material systems, synthesis methods, chirality transfer mechanisms, and applications in photodetectors. The critical role of chiral organic cations in crystal regulation and chiroptical properties along with corresponding fabrication strategies is analyzed. Then, the inherent mechanisms of chirality transfer from organic to inorganic components are thoroughly discussed, encompassing structural distortion induction and electronic orbital coupling. Subsequently, recent advances in circularly polarized photodetectors based on low-dimensional chiral perovskites are highlighted from device performance, spin selection efficiency, to bio-inspired polarization vision systems. Finally, the challenges and future directions in this field are prospected. This review provides a comprehensive summarization for the development of low-dimensional chiral perovskites and their applications in next-generation polarized photodetectors.
{"title":"Low-Dimensional Chiral Perovskites for Polarization-Sensitive Photodetection","authors":"Kaichen Wang,Yu Zhou,Bori Shi,Xiaofei Sun,Xiao Qiu,Zhiyong Fan","doi":"10.1021/acs.nanolett.6c04034","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c04034","url":null,"abstract":"Emerging low-dimensional chiral perovskites have recently demonstrated significant application potential in circularly polarized light detection, spintronics, and quantum information technology due to their unique chiroptical activity and spin-selective properties. This review systematically summarizes their material systems, synthesis methods, chirality transfer mechanisms, and applications in photodetectors. The critical role of chiral organic cations in crystal regulation and chiroptical properties along with corresponding fabrication strategies is analyzed. Then, the inherent mechanisms of chirality transfer from organic to inorganic components are thoroughly discussed, encompassing structural distortion induction and electronic orbital coupling. Subsequently, recent advances in circularly polarized photodetectors based on low-dimensional chiral perovskites are highlighted from device performance, spin selection efficiency, to bio-inspired polarization vision systems. Finally, the challenges and future directions in this field are prospected. This review provides a comprehensive summarization for the development of low-dimensional chiral perovskites and their applications in next-generation polarized photodetectors.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"58 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HfO2/ZrO2-based (HZO) materials are promising high-k dielectrics for integrated capacitors and advanced electronic devices. However, their performance is fundamentally constrained by polymorph competition and the trade-off between the dielectric constant and leakage current. Here, we report a stacking-engineered strategy that integrates HZO layers with optimized ferroelectric and dielectric properties separated by an Al2O3 interlayer (HAZO). A nonswitching pulse measurement is employed to exclude polarization-switching contributions and directly probe the intrinsic dielectric response. The optimized HAZO dielectric exhibits an enhanced dielectric constant while simultaneously suppressing leakage and improving the dielectric breakdown characteristics. Structural characterizations reveal that the engineered stacking stabilizes the coexistence of nonpolar tetragonal and polar orthorhombic phases and increases the phase-boundary density. This polymorphic configuration suppresses irreversible domain switching and enables a stable enhanced dielectric response. These results establish a robust pathway toward high-performance HZO-based dielectrics and provide key insights into tailoring dielectric properties through polymorphic-phase engineering.
{"title":"Polymorphic Hf(Zr)O2-Based Films for High-k Dielectrics","authors":"Beikai Ding,Haoyu Lu,Xuanyu Zhao,Yu Li,Li Zheng,Shiwei Xia,Qi Liu,Hao Jiang,Yingfen Wei","doi":"10.1021/acs.nanolett.6c03703","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c03703","url":null,"abstract":"HfO2/ZrO2-based (HZO) materials are promising high-k dielectrics for integrated capacitors and advanced electronic devices. However, their performance is fundamentally constrained by polymorph competition and the trade-off between the dielectric constant and leakage current. Here, we report a stacking-engineered strategy that integrates HZO layers with optimized ferroelectric and dielectric properties separated by an Al2O3 interlayer (HAZO). A nonswitching pulse measurement is employed to exclude polarization-switching contributions and directly probe the intrinsic dielectric response. The optimized HAZO dielectric exhibits an enhanced dielectric constant while simultaneously suppressing leakage and improving the dielectric breakdown characteristics. Structural characterizations reveal that the engineered stacking stabilizes the coexistence of nonpolar tetragonal and polar orthorhombic phases and increases the phase-boundary density. This polymorphic configuration suppresses irreversible domain switching and enables a stable enhanced dielectric response. These results establish a robust pathway toward high-performance HZO-based dielectrics and provide key insights into tailoring dielectric properties through polymorphic-phase engineering.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"8 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantum dot light-emitting diodes (QD-LEDs) require encapsulation to extend their storage and operational lifetime. However, acidic encapsulants commonly used usually induce an anomalous positive aging phenomenon─the device performance improves rather than decreases in the initial days. These uncontrollable gains hinder the commercialization of QD-LEDs, yet no study to date has directly probed the in situ evolution of charge carriers during this process. Here, we employ electrically excited transient absorption (EETA) spectroscopy to investigate how encapsulants influence charge carrier dynamics in QD-LEDs. Taking red QD-LEDs as a model system, we demonstrate that positive aging is accompanied by enhanced electron charging in the quantum dot (QD) layer and accelerated electron injection into the emissive layer. Furthermore, we show that acid-induced progressive passivation of surface defects on ZnMgO nanoparticles improves electron injection efficiency. This work reveals that enhanced electron charging induces positive aging in QD-LEDs.
{"title":"Enhanced Electron Charging Induces Positive Aging of QD-LEDs: An Electrically Excited Transient Absorption Study","authors":"Zhijie Yan,Bo Li,Wenjing Zhang,Yaqi Guo,Leilei Zhao,Qing Xue,Yu Yan,Xingzhi Wang,Huaiyu Xu,Xiaosuo Wang,Huaibin Shen,Fengjia Fan","doi":"10.1021/acs.nanolett.6c03813","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c03813","url":null,"abstract":"Quantum dot light-emitting diodes (QD-LEDs) require encapsulation to extend their storage and operational lifetime. However, acidic encapsulants commonly used usually induce an anomalous positive aging phenomenon─the device performance improves rather than decreases in the initial days. These uncontrollable gains hinder the commercialization of QD-LEDs, yet no study to date has directly probed the in situ evolution of charge carriers during this process. Here, we employ electrically excited transient absorption (EETA) spectroscopy to investigate how encapsulants influence charge carrier dynamics in QD-LEDs. Taking red QD-LEDs as a model system, we demonstrate that positive aging is accompanied by enhanced electron charging in the quantum dot (QD) layer and accelerated electron injection into the emissive layer. Furthermore, we show that acid-induced progressive passivation of surface defects on ZnMgO nanoparticles improves electron injection efficiency. This work reveals that enhanced electron charging induces positive aging in QD-LEDs.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"69 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-12DOI: 10.1021/acs.nanolett.6c03735
Michele Re Fiorentin,Simone Grillo,Fulvio Paleari,Olivia Pulci,Daniele Varsano,Maurizia Palummo
Chemically and structurally diverse two-dimensional semiconductors exhibit a broad range of excitonic and optical phenomena that have direct implications for optoelectronic functionality. We examine these materials from a first-principles many-body perspective, emphasizing the connection between microscopic excitonic structure and optoelectronic functionality. Reduced symmetry and orbital character produce polarization-selective absorption, while dimensionality, dielectric screening, and exciton fine structure govern binding energies and radiative behavior. In layered systems, interlayer electrostatics and type-II band alignment promote charge separation, whereas exciton–phonon coupling activates indirect optical transitions and shapes temperature-dependent spectra. These mechanisms establish common design principles for excitonic engineering, whereby the dielectric environment, crystal geometry, lattice dynamics, and stacking are used to control exciton properties and tailor optical functionality. This perspective moves beyond description toward the ab initio prediction and design of emerging 2D materials for targeted optoelectronic applications, including polarization-sensitive photodetection and ultrathin solar-energy conversion.
{"title":"Excitonic Physics in Emerging 2D Semiconductors: A First-Principles Many-Body Perspective from Photodetection to Solar Energy Conversion","authors":"Michele Re Fiorentin,Simone Grillo,Fulvio Paleari,Olivia Pulci,Daniele Varsano,Maurizia Palummo","doi":"10.1021/acs.nanolett.6c03735","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c03735","url":null,"abstract":"Chemically and structurally diverse two-dimensional semiconductors exhibit a broad range of excitonic and optical phenomena that have direct implications for optoelectronic functionality. We examine these materials from a first-principles many-body perspective, emphasizing the connection between microscopic excitonic structure and optoelectronic functionality. Reduced symmetry and orbital character produce polarization-selective absorption, while dimensionality, dielectric screening, and exciton fine structure govern binding energies and radiative behavior. In layered systems, interlayer electrostatics and type-II band alignment promote charge separation, whereas exciton–phonon coupling activates indirect optical transitions and shapes temperature-dependent spectra. These mechanisms establish common design principles for excitonic engineering, whereby the dielectric environment, crystal geometry, lattice dynamics, and stacking are used to control exciton properties and tailor optical functionality. This perspective moves beyond description toward the ab initio prediction and design of emerging 2D materials for targeted optoelectronic applications, including polarization-sensitive photodetection and ultrathin solar-energy conversion.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"53 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-12DOI: 10.1021/acs.nanolett.6c03982
Amirehsan Alizadehherfati,Yuxi Jiang,Kelsey J. Mirrielees,Nils von den Driesch,Christine Falter,Yurii Kutovyi,Amirehsan Boreiri,Douglas L. Irving,Alexander Pawlis,Edo Waks
Semiconductor hole spins offer a pathway to extended coherence times by decoupling from nuclear magnetic noise, while their spin–orbit coupling enables fast all-electrical control. In ZnSe, however, realizing this potential has been limited by p-doping challenges. Here, we circumvent this limit by optically activating acceptors and demonstrate optical spin initialization. We isolate a single-hole spin bound to a shallow acceptor, confirmed by antibunching and accessed via the fast (244 ps) radiative recombination of a bound exciton. Magnetic and Raman spectroscopy reveal a spin-selective Λ system with an effective hole g-factor of 0.7 and an optical line width of 26.7 GHz. Time-resolved measurements reveal optical pumping of the hole spin with an estimated initialization fidelity of 90.7%. First-principles simulations combined with the experiment identify nitrogen as the most likely acceptor impurity. These results introduce a promising new platform for optically active spin qubits and single-photon sources in ZnSe.
{"title":"Optically Active Single Hole Spin in ZnSe","authors":"Amirehsan Alizadehherfati,Yuxi Jiang,Kelsey J. Mirrielees,Nils von den Driesch,Christine Falter,Yurii Kutovyi,Amirehsan Boreiri,Douglas L. Irving,Alexander Pawlis,Edo Waks","doi":"10.1021/acs.nanolett.6c03982","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c03982","url":null,"abstract":"Semiconductor hole spins offer a pathway to extended coherence times by decoupling from nuclear magnetic noise, while their spin–orbit coupling enables fast all-electrical control. In ZnSe, however, realizing this potential has been limited by p-doping challenges. Here, we circumvent this limit by optically activating acceptors and demonstrate optical spin initialization. We isolate a single-hole spin bound to a shallow acceptor, confirmed by antibunching and accessed via the fast (244 ps) radiative recombination of a bound exciton. Magnetic and Raman spectroscopy reveal a spin-selective Λ system with an effective hole g-factor of 0.7 and an optical line width of 26.7 GHz. Time-resolved measurements reveal optical pumping of the hole spin with an estimated initialization fidelity of 90.7%. First-principles simulations combined with the experiment identify nitrogen as the most likely acceptor impurity. These results introduce a promising new platform for optically active spin qubits and single-photon sources in ZnSe.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"9 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hyperbolic media support high-k electromagnetic modes, enabling subdiffractional confinement, anomalous refraction, and enhanced light–matter interactions. While most hyperbolic metamaterials rely on artificial structuring, natural hyperbolicity arises from crystal anisotropy and direction-dependent plasma frequencies. Here we provide direct experimental evidence for natural hyperbolicity in copper chalcogenides by spectroscopic ellipsometry in the visible–near-infrared range. We demonstrate hyperbolic dispersion in bulk covellite CuS by identifying a spectral window where the real parts of the in-plane and out-of-plane permittivity components have opposite signs. The study is then expanded to size-controlled CuS nanosheets as oriented films. Using the Bruggeman effective medium approximation to account for the nanostructure/void composite, we show that hyperbolicity persists upon nanoscaling and that the epsilon-near-zero condition and hyperbolic bandwidth shift with size. Finally, we demonstrate analogous behavior in klockmannite CuSe nanosheets, establishing copper chalcogenides as a tunable platform for natural hyperbolicity at the boundary of the NIR and visible ranges.
{"title":"Natural Hyperbolic Dispersion in Anisotropic Bulk and Nanoscaled Copper Chalcogenides","authors":"Urvi Parekh,Achyut Tiwari,Bruno Gompf,Nadiia Didukh,Jivesh Kaushal,Stefan Scheel,Christian Klinke,Rostyslav Lesyuk","doi":"10.1021/acs.nanolett.6c02585","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c02585","url":null,"abstract":"Hyperbolic media support high-k electromagnetic modes, enabling subdiffractional confinement, anomalous refraction, and enhanced light–matter interactions. While most hyperbolic metamaterials rely on artificial structuring, natural hyperbolicity arises from crystal anisotropy and direction-dependent plasma frequencies. Here we provide direct experimental evidence for natural hyperbolicity in copper chalcogenides by spectroscopic ellipsometry in the visible–near-infrared range. We demonstrate hyperbolic dispersion in bulk covellite CuS by identifying a spectral window where the real parts of the in-plane and out-of-plane permittivity components have opposite signs. The study is then expanded to size-controlled CuS nanosheets as oriented films. Using the Bruggeman effective medium approximation to account for the nanostructure/void composite, we show that hyperbolicity persists upon nanoscaling and that the epsilon-near-zero condition and hyperbolic bandwidth shift with size. Finally, we demonstrate analogous behavior in klockmannite CuSe nanosheets, establishing copper chalcogenides as a tunable platform for natural hyperbolicity at the boundary of the NIR and visible ranges.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"21 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electronic phases in quantum materials are often governed by nanoscale inhomogeneity, where local order develops within spatially confined regions, or puddles. A prominent example is an incommensurate charge-density-wave (I-CDW) comprising locally commensurate domains. In 2H-NbSe2, such an I-CDW state persists alongside lattice anharmonicity and superconductivity, raising fundamental questions about the dynamical stabilization of CDW order in puddles. Here, using Raman scattering, we reveal a strong Fano-coupling between interlayer shear phonons and the CDW amplitude mode. Our time-resolved reflectivity measurement shows a low-frequency ∼0.2 THz coherent overdamped oscillation onsetting within the CDW regime at ∼17K, indicating a previously unexplored transition. This we identify as a Fano-coupled phonon-CDW hybrid emerging from the collective dynamics of CDW puddles. We establish an overdamped-oscillator framework for capturing such intertwined glassy dynamics. These results highlight how lattice pinning and electronic correlations shape CDW order in layered materials, insight crucial for designing novel van der Waals devices.
{"title":"Dynamics of Charge-Density-Wave Puddles in 2H-NbSe2","authors":"Shreya Kumbhakar,Marina Esposito,Anjan Kumar N M,Liwen Feng,Tommaso Confalone,Vasilisa Gerega,Flavia Lo Sardo,Rafiqul Alam,Davide Masarotti,Francesco Tafuri,Thomas Böhm,Mahmoud Abdel-Hafiez,Sushmita Chandra,Claudia Felser,Kornelius Nielsch,Nicola Poccia,Stefan Kaiser,Golam Haider","doi":"10.1021/acs.nanolett.6c03967","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c03967","url":null,"abstract":"Electronic phases in quantum materials are often governed by nanoscale inhomogeneity, where local order develops within spatially confined regions, or puddles. A prominent example is an incommensurate charge-density-wave (I-CDW) comprising locally commensurate domains. In 2H-NbSe2, such an I-CDW state persists alongside lattice anharmonicity and superconductivity, raising fundamental questions about the dynamical stabilization of CDW order in puddles. Here, using Raman scattering, we reveal a strong Fano-coupling between interlayer shear phonons and the CDW amplitude mode. Our time-resolved reflectivity measurement shows a low-frequency ∼0.2 THz coherent overdamped oscillation onsetting within the CDW regime at ∼17K, indicating a previously unexplored transition. This we identify as a Fano-coupled phonon-CDW hybrid emerging from the collective dynamics of CDW puddles. We establish an overdamped-oscillator framework for capturing such intertwined glassy dynamics. These results highlight how lattice pinning and electronic correlations shape CDW order in layered materials, insight crucial for designing novel van der Waals devices.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"10 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-10DOI: 10.1021/acs.nanolett.6c03822
Chaoqin He,Xiuwen Zheng,Jingzhi Zhou,Ruo Yuan,Ying Zhuo,Xia Yang
Abstract Surface-enhanced Raman scattering (SERS) is attractive for multiplex bioimaging owing to its excellent photostability and ultranarrow spectral bandwidth. However, achieving synergistic enhancement of excitation and Raman scattering fields remains challenging. Herein, the relationship between geometry and localized surface plasmon resonance (LSPR) was investigated by continuously tuning the aspect ratio (AR) of anisotropic Au nanopolyhedrons (Au NPHs). Central-body modulation while preserving sharp terminal tips enables continuous LSPR tuning while retaining tip-associated electromagnetic enhancement. The SERS behavior was further analyzed by considering the spectral matching between the LSPR and the excitation/scattering wavelengths. For different excitation wavelengths, the optimal SERS response can be achieved by selecting Au NPHs whose LSPR band best matches with the excitation and Raman scattering wavelengths. These results demonstrate that Raman enhancement is governed by spectral matching rather than a fixed optimal geometry. The optimized Au NPHs enabled the use of dual SERS probes for proof-of-concept multiplex biomarker imaging.
{"title":"Continuously\u0000Tunable Localized Surface Plasmon Resonance\u0000of Anisotropic Gold Nanopolyhedrons for Multiplexed Surface-Enhanced\u0000Raman Scattering Imaging","authors":"Chaoqin He,Xiuwen Zheng,Jingzhi Zhou,Ruo Yuan,Ying Zhuo,Xia Yang","doi":"10.1021/acs.nanolett.6c03822","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c03822","url":null,"abstract":"Abstract Surface-enhanced Raman scattering (SERS) is attractive for multiplex bioimaging owing to its excellent photostability and ultranarrow spectral bandwidth. However, achieving synergistic enhancement of excitation and Raman scattering fields remains challenging. Herein, the relationship between geometry and localized surface plasmon resonance (LSPR) was investigated by continuously tuning the aspect ratio (AR) of anisotropic Au nanopolyhedrons (Au NPHs). Central-body modulation while preserving sharp terminal tips enables continuous LSPR tuning while retaining tip-associated electromagnetic enhancement. The SERS behavior was further analyzed by considering the spectral matching between the LSPR and the excitation/scattering wavelengths. For different excitation wavelengths, the optimal SERS response can be achieved by selecting Au NPHs whose LSPR band best matches with the excitation and Raman scattering wavelengths. These results demonstrate that Raman enhancement is governed by spectral matching rather than a fixed optimal geometry. The optimized Au NPHs enabled the use of dual SERS probes for proof-of-concept multiplex biomarker imaging.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"15 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-10DOI: 10.1021/acs.nanolett.6c04038
Anya S. Mulligan,Guomin Zhu,Ece Genc,Eric Cui,Stephen D. Wilson,Susanne Stemmer
Abstract Probing the internal electronic structure of complex materials with atomic spatial resolution has remained an outstanding challenge in condensed-matter science. A promising approach is convergent-beam electron diffraction (CBED) in four-dimensional scanning transmission electron microscopy (4D-STEM). Here, we apply 4D-STEM CBED to the charge-density-wave (CDW) material 1T-TaS2. We demonstrate a qualitative breakdown of the conventional independent atom model (IAM) in reproducing the experimental CBED patterns. A robust low-angle intensity maximum is systematically absent in IAM-based simulations but is consistently reproduced in simulations that use electrostatic potentials derived from density functional theory. A comparison of CBED patterns with projected charge densities reveals a remarkable correspondence between the local real-space valence charge distribution and diffracted intensities, reflecting site-dependent charge density variations within the CDW structure. These results establish atomic-resolution CBED as an experimental probe of valence electron contributions to the scattering potential and open a route to resolving complex electronic ordering phenomena.
{"title":"Probing Valence\u0000Electron Distributions at Subatomic\u0000Resolution in a Charge Density Wave Material","authors":"Anya S. Mulligan,Guomin Zhu,Ece Genc,Eric Cui,Stephen D. Wilson,Susanne Stemmer","doi":"10.1021/acs.nanolett.6c04038","DOIUrl":"https://doi.org/10.1021/acs.nanolett.6c04038","url":null,"abstract":"Abstract Probing the internal electronic structure of complex materials with atomic spatial resolution has remained an outstanding challenge in condensed-matter science. A promising approach is convergent-beam electron diffraction (CBED) in four-dimensional scanning transmission electron microscopy (4D-STEM). Here, we apply 4D-STEM CBED to the charge-density-wave (CDW) material 1T-TaS2. We demonstrate a qualitative breakdown of the conventional independent atom model (IAM) in reproducing the experimental CBED patterns. A robust low-angle intensity maximum is systematically absent in IAM-based simulations but is consistently reproduced in simulations that use electrostatic potentials derived from density functional theory. A comparison of CBED patterns with projected charge densities reveals a remarkable correspondence between the local real-space valence charge distribution and diffracted intensities, reflecting site-dependent charge density variations within the CDW structure. These results establish atomic-resolution CBED as an experimental probe of valence electron contributions to the scattering potential and open a route to resolving complex electronic ordering phenomena.","PeriodicalId":53,"journal":{"name":"Nano Letters","volume":"6 1","pages":""},"PeriodicalIF":10.8,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149151547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：