Takeshi Odagawa, Sota Yamamoto, Chaoliang Zhang, Kazuki Koyama, Jun Ishihara, Giacomo Mariani, Yoji Kunihashi, Haruki Sanada, Junsaku Nitta, Makoto Kohda
We investigate the excitonic species in WS2 monolayers transferred onto III–V semiconductor substrates with different surface treatments. When the III–V substrates were covered with amorphous native oxides, negatively charged excitons dominated the spectral weight in low-temperature near-resonance photoluminescence (PL) measurements. However, when the native oxides of the III–V substrates were reduced, neutral excitons began to dominate the spectral weight, indicating a reduction in the electron density in the WS2 monolayers. The removal of the native oxides enhanced the electron transfer from the WS2 monolayer to the III–V substrate. In addition, an additional shoulder-like PL feature appeared ∼50 meV below the emission of neutral excitons, which can be attributed to the emission of localized excitons. When the III–V substrate surface was passivated by sulfur after the reduction of the native oxides, neutral excitons still dominated the spectral weight. However, the low-energy PL shoulder disappeared again, suggesting the effective delocalization of excitons through substrate surface passivation. Surface engineering of the semiconductor substrates for two-dimensional (2D) materials can provide a novel approach to control the carrier density of the 2D materials, implement deterministic carrier localization or delocalization for the 2D materials, and facilitate the interlayer transfer of charge, spin, and valley currents. These findings open the avenue for novel device concepts and phenomena in mixed-dimensional semiconductor heterostructures.
{"title":"Enhanced interlayer electron transfer by surface treatments in mixed-dimensional van der Waals semiconductor heterostructures","authors":"Takeshi Odagawa, Sota Yamamoto, Chaoliang Zhang, Kazuki Koyama, Jun Ishihara, Giacomo Mariani, Yoji Kunihashi, Haruki Sanada, Junsaku Nitta, Makoto Kohda","doi":"10.1063/5.0214718","DOIUrl":"https://doi.org/10.1063/5.0214718","url":null,"abstract":"We investigate the excitonic species in WS2 monolayers transferred onto III–V semiconductor substrates with different surface treatments. When the III–V substrates were covered with amorphous native oxides, negatively charged excitons dominated the spectral weight in low-temperature near-resonance photoluminescence (PL) measurements. However, when the native oxides of the III–V substrates were reduced, neutral excitons began to dominate the spectral weight, indicating a reduction in the electron density in the WS2 monolayers. The removal of the native oxides enhanced the electron transfer from the WS2 monolayer to the III–V substrate. In addition, an additional shoulder-like PL feature appeared ∼50 meV below the emission of neutral excitons, which can be attributed to the emission of localized excitons. When the III–V substrate surface was passivated by sulfur after the reduction of the native oxides, neutral excitons still dominated the spectral weight. However, the low-energy PL shoulder disappeared again, suggesting the effective delocalization of excitons through substrate surface passivation. Surface engineering of the semiconductor substrates for two-dimensional (2D) materials can provide a novel approach to control the carrier density of the 2D materials, implement deterministic carrier localization or delocalization for the 2D materials, and facilitate the interlayer transfer of charge, spin, and valley currents. These findings open the avenue for novel device concepts and phenomena in mixed-dimensional semiconductor heterostructures.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"40 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sourav Chowdhury, Anupam Jana, Ritu Rawat, Priyanka Yadav, Rajibul Islam, Fei Xue, A. K. Mandal, Sumit Sarkar, Rajan Mishra, R. Venkatesh, D. M. Phase, R. J. Choudhary
Ferromagnetic insulators (FMIs) have widespread applications in microwave devices, magnetic tunneling junctions, and dissipationless electronic and quantum-spintronic devices. However, the sparsity of the available high-temperature FMIs has led to the quest for a robust and controllable insulating ferromagnetic state. Here, we present compelling evidence of modulation of the magnetic ground state in a SrCoO2.5 (SCO) thin film via strain engineering. The SCO system is an antiferromagnetic insulator with a Neel temperature, TN, of ∼550 K. Applying in-plane compressive strain, the SCO thin film reveals an insulating ferromagnetic state with an extraordinarily high Curie temperature, TC, of ∼750 K. The emerged ferromagnetic state is associated with charge-disproportionation (CD) and spin-state-disproportionation (SSD), involving high-spin Co2+ and low-spin Co4+ ions. The density functional theory calculation also produces an insulating ferromagnetic state in the strained SCO system, consistent with the CD and SSD, which is associated with the structural ordering in the system. Transpiring the insulating ferromagnetic state through modulating the electronic correlation parameters via strain engineering in the SCO thin film will have a significant impact in large areas of modern electronic and spintronic applications.
{"title":"High-temperature insulating ferromagnetic state in charge-disproportionated and spin-state-disproportionated strained SrCoO2.5 thin film","authors":"Sourav Chowdhury, Anupam Jana, Ritu Rawat, Priyanka Yadav, Rajibul Islam, Fei Xue, A. K. Mandal, Sumit Sarkar, Rajan Mishra, R. Venkatesh, D. M. Phase, R. J. Choudhary","doi":"10.1063/5.0188767","DOIUrl":"https://doi.org/10.1063/5.0188767","url":null,"abstract":"Ferromagnetic insulators (FMIs) have widespread applications in microwave devices, magnetic tunneling junctions, and dissipationless electronic and quantum-spintronic devices. However, the sparsity of the available high-temperature FMIs has led to the quest for a robust and controllable insulating ferromagnetic state. Here, we present compelling evidence of modulation of the magnetic ground state in a SrCoO2.5 (SCO) thin film via strain engineering. The SCO system is an antiferromagnetic insulator with a Neel temperature, TN, of ∼550 K. Applying in-plane compressive strain, the SCO thin film reveals an insulating ferromagnetic state with an extraordinarily high Curie temperature, TC, of ∼750 K. The emerged ferromagnetic state is associated with charge-disproportionation (CD) and spin-state-disproportionation (SSD), involving high-spin Co2+ and low-spin Co4+ ions. The density functional theory calculation also produces an insulating ferromagnetic state in the strained SCO system, consistent with the CD and SSD, which is associated with the structural ordering in the system. Transpiring the insulating ferromagnetic state through modulating the electronic correlation parameters via strain engineering in the SCO thin film will have a significant impact in large areas of modern electronic and spintronic applications.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"1009 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three-dimensional reciprocal space mapping (3D-RSM) offers crucial insights into the intricate microstructural properties of materials, including spatial domain distribution, directional long-range ordering, multilayer-substrate mismatch, layer tilting, and defect structure. Traditionally, 3D-RSMs are conducted at synchrotron facilities where instrumental resolution is constrained in all three directions. Lab-based sources have often been considered suboptimal for 3D-RSM measurements due to poor instrumental resolution along the axial direction. However, we demonstrate that, by employing three-dimensional reciprocal space x-ray computed tomography (RS-XCT), the same perceived limitation in resolution can be effectively leveraged to acquire high quality 3D-RSMs. Through a combination of ultrafast reciprocal space mapping and computed tomography reconstruction routines, lab-based 3D-RSMs achieve resolutions comparable to those obtained with synchrotron-based techniques. RS-XCT introduces a practical modality for lab-based x-ray diffractometers, enabling high-resolution 3D-RSM measurements on a variety of materials exhibiting complex three-dimensional scattering landscapes in reciprocal space.
三维倒易空间制图（3D-RSM）可帮助人们深入了解材料错综复杂的微观结构特性，包括空间畴分布、定向长程有序、多层衬底错配、层倾斜和缺陷结构。传统上，3D-RSM 是在同步辐射设施中进行的，在同步辐射设施中，仪器在所有三个方向上的分辨率都受到限制。由于沿轴向的仪器分辨率较低，基于实验室的光源通常被认为是 3D-RSM 测量的次优选择。然而，我们证明，通过采用三维往复空间 X 射线计算机断层扫描 (RS-XCT)，可以有效地利用同样的分辨率限制来获取高质量的三维 RSM。通过结合超快倒易空间映射和计算机断层扫描重建程序，基于实验室的三维 RSM 可达到与同步加速器技术相媲美的分辨率。RS-XCT 为基于实验室的 X 射线衍射仪引入了一种实用模式，可对在倒易空间呈现复杂三维散射景观的各种材料进行高分辨率 3D-RSM 测量。
{"title":"Reciprocal space x-ray computed tomography","authors":"Arturas Vailionis, Liyan Wu, Jonathan E. Spanier","doi":"10.1063/5.0203995","DOIUrl":"https://doi.org/10.1063/5.0203995","url":null,"abstract":"Three-dimensional reciprocal space mapping (3D-RSM) offers crucial insights into the intricate microstructural properties of materials, including spatial domain distribution, directional long-range ordering, multilayer-substrate mismatch, layer tilting, and defect structure. Traditionally, 3D-RSMs are conducted at synchrotron facilities where instrumental resolution is constrained in all three directions. Lab-based sources have often been considered suboptimal for 3D-RSM measurements due to poor instrumental resolution along the axial direction. However, we demonstrate that, by employing three-dimensional reciprocal space x-ray computed tomography (RS-XCT), the same perceived limitation in resolution can be effectively leveraged to acquire high quality 3D-RSMs. Through a combination of ultrafast reciprocal space mapping and computed tomography reconstruction routines, lab-based 3D-RSMs achieve resolutions comparable to those obtained with synchrotron-based techniques. RS-XCT introduces a practical modality for lab-based x-ray diffractometers, enabling high-resolution 3D-RSM measurements on a variety of materials exhibiting complex three-dimensional scattering landscapes in reciprocal space.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"46 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nicolai Grund, Dirk Holland-Moritz, Saba Khademorezaian, Lucas P. Kreuzer, Nico Neuber, Lucas M. Ruschel, Hendrik Voigt, Johanna Wilden, Fan Yang, Soham Banerjee, Malte Blankenburg, Ann-Christin Dippel, Jan Peter Embs, Sergiy Divinski, Ralf Busch, Andreas Meyer, Gerhard Wilde
We investigated the change in the structure and dynamics of a Ni–Nb bulk metallic glass upon sulfur addition on both microscopic and macroscopic scales. With the sulfur concentration of 3 at. %, where the composition Ni58Nb39S3 exhibits the best glass forming ability in the investigated sulfur concentration range, both the equilibrium and undercooled melt dynamics remain almost unchanged. Only in the glassy state does sulfur seem to result in mass transport less decoupled to the viscosity of the undercooled liquid, where the measured Ag tracer diffusion coefficient is slower in the ternary alloy. With the structural disorder introduced by the alloying sulfur, the improved glass forming ability is attributed to geometrical frustration, where crystal nucleation requires a depletion of sulfur and hence long range diffusion, as long as no primary sulfur-containing crystalline phase is involved.
{"title":"Impact of sulfur addition on the structure and dynamics of Ni–Nb alloy melts","authors":"Nicolai Grund, Dirk Holland-Moritz, Saba Khademorezaian, Lucas P. Kreuzer, Nico Neuber, Lucas M. Ruschel, Hendrik Voigt, Johanna Wilden, Fan Yang, Soham Banerjee, Malte Blankenburg, Ann-Christin Dippel, Jan Peter Embs, Sergiy Divinski, Ralf Busch, Andreas Meyer, Gerhard Wilde","doi":"10.1063/5.0205058","DOIUrl":"https://doi.org/10.1063/5.0205058","url":null,"abstract":"We investigated the change in the structure and dynamics of a Ni–Nb bulk metallic glass upon sulfur addition on both microscopic and macroscopic scales. With the sulfur concentration of 3 at. %, where the composition Ni58Nb39S3 exhibits the best glass forming ability in the investigated sulfur concentration range, both the equilibrium and undercooled melt dynamics remain almost unchanged. Only in the glassy state does sulfur seem to result in mass transport less decoupled to the viscosity of the undercooled liquid, where the measured Ag tracer diffusion coefficient is slower in the ternary alloy. With the structural disorder introduced by the alloying sulfur, the improved glass forming ability is attributed to geometrical frustration, where crystal nucleation requires a depletion of sulfur and hence long range diffusion, as long as no primary sulfur-containing crystalline phase is involved.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"27 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tae Eon Kim, Sunghoon Jung, Soo Hyun Lee, ChaeWon Mun, Eun-Yeon Byeon, Jun-Yeong Yang, Jucheol Park, Seunghun Lee, Heemin Kang, Sung-Gyu Park
The trade-off relationship between cost and performance is a major challenge in the development of surface-enhanced Raman spectroscopy (SERS) sensors for practical applications. We propose a roll-to-roll system with incorporated vacuum sputtering to manufacture Ag-coated nanodimples (Ag/NDs) on A4-scale films in a single step. The Ag/ND SERS platforms were prepared via O2 ion beam sputtering and Ag sputtering deposition. The concave three-dimensional spaces in the Ag/NDs functioned as hotspots, and their optimal fabrication conditions were investigated with two variables: moving speed and Ag thickness. The entire process was automated, which resulted in highly consistent optical responses (i.e., relative standard deviation of ∼10%). The activation of plasmonic hotspots was demonstrated by electric-field profiles calculated via the finite-difference time-domain method. The wavelength dependency of the Ag/ND platforms was also examined by dark-field microscopy. The results indicate that the developed engineering technique for the large-scale production of Ag/ND plasmonic chips would likely be competitive in the commercial market.
在开发实际应用的表面增强拉曼光谱（SERS）传感器时，成本与性能之间的权衡关系是一大挑战。我们提出了一种结合真空溅射的辊对辊系统，可在 A4 级薄膜上一步制备 Ag 涂层纳米微粒（Ag/ND）。Ag/ND SERS 平台是通过 O2 离子束溅射和 Ag 溅射沉积制备的。Ag/ND 中的凹面三维空间起到了热点的作用，通过两个变量：移动速度和 Ag 厚度，研究了其最佳制备条件。整个过程都是自动化的，因此产生了高度一致的光学响应（即相对标准偏差∼10%）。通过有限差分时域法计算的电场曲线证明了等离子热点的激活。此外，还通过暗场显微镜检查了 Ag/ND 平台的波长依赖性。结果表明，所开发的大规模生产 Ag/ND 等离子芯片的工程技术很可能在商业市场上具有竞争力。
{"title":"Development of one-step roll-to-roll system with incorporated vacuum sputtering for large-scale production of plasmonic sensing chips","authors":"Tae Eon Kim, Sunghoon Jung, Soo Hyun Lee, ChaeWon Mun, Eun-Yeon Byeon, Jun-Yeong Yang, Jucheol Park, Seunghun Lee, Heemin Kang, Sung-Gyu Park","doi":"10.1063/5.0211084","DOIUrl":"https://doi.org/10.1063/5.0211084","url":null,"abstract":"The trade-off relationship between cost and performance is a major challenge in the development of surface-enhanced Raman spectroscopy (SERS) sensors for practical applications. We propose a roll-to-roll system with incorporated vacuum sputtering to manufacture Ag-coated nanodimples (Ag/NDs) on A4-scale films in a single step. The Ag/ND SERS platforms were prepared via O2 ion beam sputtering and Ag sputtering deposition. The concave three-dimensional spaces in the Ag/NDs functioned as hotspots, and their optimal fabrication conditions were investigated with two variables: moving speed and Ag thickness. The entire process was automated, which resulted in highly consistent optical responses (i.e., relative standard deviation of ∼10%). The activation of plasmonic hotspots was demonstrated by electric-field profiles calculated via the finite-difference time-domain method. The wavelength dependency of the Ag/ND platforms was also examined by dark-field microscopy. The results indicate that the developed engineering technique for the large-scale production of Ag/ND plasmonic chips would likely be competitive in the commercial market.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"21 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141198245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Mattern, J. Jarecki, J. A. Arregi, V. Uhlíř, M. Rössle, M. Bargheer
We use ultrafast x-ray diffraction and the polar time-resolved magneto-optical Kerr effect to study the laser-induced metamagnetic phase transition in two FeRh films with thicknesses below and above the optical penetration depth. In the thin film, we identify an intrinsic timescale for the light-induced nucleation of ferromagnetic (FM) domains in the antiferromagnetic material of 8ps, which is substantially longer than the time it takes for strain waves to traverse the film. For the inhomogeneously excited thicker film, only the optically excited near-surface part transforms within 8ps. For strong excitations, we observe an additional slow rise of the FM phase, which we experimentally relate to a growth of the FM phase into the depth of the layer by comparing the transient magnetization in frontside and backside excitation geometry. In the lower lying parts of the film, which are only excited via near-equilibrium heat transport, the FM phase emerges significantly slower than 8ps after heating above the transition temperature.
我们利用超快 X 射线衍射和极地时间分辨磁光克尔效应，研究了厚度低于和高于光学穿透深度的两层 FeRh 薄膜中激光诱导的元磁相变。在薄膜中，我们确定了反铁磁材料中铁磁（FM）畴的光诱导成核的固有时间尺度为 8ps，大大长于应变波穿过薄膜所需的时间。对于不均匀激发的较厚薄膜，只有光学激发的近表面部分会在 8ps 内发生转变。对于强激励，我们观察到调频相的额外缓慢上升，通过比较正面和背面激励几何形状下的瞬态磁化，我们在实验中将其与调频相向膜层深处的增长联系起来。在薄膜的低层部分，仅通过近平衡热传导激发，调频相在加热到转变温度以上后出现的速度明显慢于 8ps。
{"title":"Speed limits of the laser-induced phase transition in FeRh","authors":"M. Mattern, J. Jarecki, J. A. Arregi, V. Uhlíř, M. Rössle, M. Bargheer","doi":"10.1063/5.0206095","DOIUrl":"https://doi.org/10.1063/5.0206095","url":null,"abstract":"We use ultrafast x-ray diffraction and the polar time-resolved magneto-optical Kerr effect to study the laser-induced metamagnetic phase transition in two FeRh films with thicknesses below and above the optical penetration depth. In the thin film, we identify an intrinsic timescale for the light-induced nucleation of ferromagnetic (FM) domains in the antiferromagnetic material of 8ps, which is substantially longer than the time it takes for strain waves to traverse the film. For the inhomogeneously excited thicker film, only the optically excited near-surface part transforms within 8ps. For strong excitations, we observe an additional slow rise of the FM phase, which we experimentally relate to a growth of the FM phase into the depth of the layer by comparing the transient magnetization in frontside and backside excitation geometry. In the lower lying parts of the film, which are only excited via near-equilibrium heat transport, the FM phase emerges significantly slower than 8ps after heating above the transition temperature.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141170950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohan K. Bhattarai, Balram Tripathi, Shweta Shweta, Satyam Kumar, Claudia C. Zuluaga-Gómez, Rajesh K. Katiyar, Brad R. Weiner, Ram S. Katiyar, Gerardo Morell
Lithium–sulfur batteries (LiSBs) offer high energy density, cost-effectiveness, and eco-friendliness, making them promising for future energy storage. This study explores using BiFeO3 (BFO) nanoparticles (NPs) to tackle challenges such as lithium polysulfides (LiPs) and shuttle issues in LiSBs. It employs a solid-state melt diffusion technique, encapsulates sulfur in single-walled carbon nanotubes (SCNTs), and utilizes BFO for effective polysulfide control. Herein, composite cathodes of sulfur (S)/SCNTs (abbr. SCNT) were fabricated, and cells were designed using a BFO-coated separator (SCNT-BFS). In addition, a cathode modification was performed with composite S/SCNTs/BFO (SCNT-BF), and a comparative analysis was conducted to assess the effectiveness of the BFO in the separator and the cathode. Cyclic voltammetry measurements revealed that the increased current peak intensity at lower reduction potential in SCNT-BF and SCNT-BFS indicated control of higher-order LiPs (Li2Sx, where 4 ≤ x ≤ 8), resulting in the generation of more stable lower-order products (Li2S2/Li2S). The charge/discharge analysis revealed controlled LiPs, resulting in high-capacity retention in SCNT-BF (∼75%) and SCNT-BFS (∼88%) over 200 cycles, which yielded capacities of 526 and 700 mAh/g at C/8 (1C = 1675 mA/g). These promising results suggest that incorporating BFO into the cathode and separator can advance the commercialization of durable LiSBs.
{"title":"Effective polysulfide control in lithium–sulfur batteries utilizing BiFeO3 nanoparticles","authors":"Mohan K. Bhattarai, Balram Tripathi, Shweta Shweta, Satyam Kumar, Claudia C. Zuluaga-Gómez, Rajesh K. Katiyar, Brad R. Weiner, Ram S. Katiyar, Gerardo Morell","doi":"10.1063/5.0209845","DOIUrl":"https://doi.org/10.1063/5.0209845","url":null,"abstract":"Lithium–sulfur batteries (LiSBs) offer high energy density, cost-effectiveness, and eco-friendliness, making them promising for future energy storage. This study explores using BiFeO3 (BFO) nanoparticles (NPs) to tackle challenges such as lithium polysulfides (LiPs) and shuttle issues in LiSBs. It employs a solid-state melt diffusion technique, encapsulates sulfur in single-walled carbon nanotubes (SCNTs), and utilizes BFO for effective polysulfide control. Herein, composite cathodes of sulfur (S)/SCNTs (abbr. SCNT) were fabricated, and cells were designed using a BFO-coated separator (SCNT-BFS). In addition, a cathode modification was performed with composite S/SCNTs/BFO (SCNT-BF), and a comparative analysis was conducted to assess the effectiveness of the BFO in the separator and the cathode. Cyclic voltammetry measurements revealed that the increased current peak intensity at lower reduction potential in SCNT-BF and SCNT-BFS indicated control of higher-order LiPs (Li2Sx, where 4 ≤ x ≤ 8), resulting in the generation of more stable lower-order products (Li2S2/Li2S). The charge/discharge analysis revealed controlled LiPs, resulting in high-capacity retention in SCNT-BF (∼75%) and SCNT-BFS (∼88%) over 200 cycles, which yielded capacities of 526 and 700 mAh/g at C/8 (1C = 1675 mA/g). These promising results suggest that incorporating BFO into the cathode and separator can advance the commercialization of durable LiSBs.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"83 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141166878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miguel A. Betancourt-Ponce, Rui Liu, Jian Sun, Paul G. Evans, Padma Gopalan
A combination of block copolymer (BCP) lithography and solid-phase epitaxy can be employed to form large areas, on the order of square centimeters, of a high density of epitaxial crystalline complex oxide nanostructures. We have used BCP lithography with a poly(styrene-block-methyl methacrylate) (PS-b-PMMA) copolymer to template a nanohole array either directly on an (001)-oriented SrTiO3 (STO) single crystal substrate or on a 20 nm-thick Si3N4 layer deposited on the STO substrate. BCPs with the selected compositions assembled in a cylindrical phase with 16 nm diameter PMMA cylinders and a cylinder-to-cylinder spacing of 32 nm. The substrate was modified with an energetically non-preferential polymer layer to allow for the vertical alignment of the cylinders. The PMMA cylinders were removed using a subtractive process, leaving an array of cylindrical holes. For BCPs assembled on Si3N4/STO, the pattern was transferred to the Si3N4 layer using reactive ion etching, exposing the underlying STO substrate in the nanoholes. An amorphous LaAlO3 (LAO) layer was deposited on the patterned Si3N4/STO at room temperature. The amorphous LAO epitaxially crystallized within the nanoscale-patterned holes with fully relaxed lattice parameters through solid phase epitaxy, resulting in the formation of nanoscale LAO/STO epitaxial heterostructures.
{"title":"Patterning and epitaxy of large-area arrays of nanoscale complex oxide epitaxial heterostructures","authors":"Miguel A. Betancourt-Ponce, Rui Liu, Jian Sun, Paul G. Evans, Padma Gopalan","doi":"10.1063/5.0203258","DOIUrl":"https://doi.org/10.1063/5.0203258","url":null,"abstract":"A combination of block copolymer (BCP) lithography and solid-phase epitaxy can be employed to form large areas, on the order of square centimeters, of a high density of epitaxial crystalline complex oxide nanostructures. We have used BCP lithography with a poly(styrene-block-methyl methacrylate) (PS-b-PMMA) copolymer to template a nanohole array either directly on an (001)-oriented SrTiO3 (STO) single crystal substrate or on a 20 nm-thick Si3N4 layer deposited on the STO substrate. BCPs with the selected compositions assembled in a cylindrical phase with 16 nm diameter PMMA cylinders and a cylinder-to-cylinder spacing of 32 nm. The substrate was modified with an energetically non-preferential polymer layer to allow for the vertical alignment of the cylinders. The PMMA cylinders were removed using a subtractive process, leaving an array of cylindrical holes. For BCPs assembled on Si3N4/STO, the pattern was transferred to the Si3N4 layer using reactive ion etching, exposing the underlying STO substrate in the nanoholes. An amorphous LaAlO3 (LAO) layer was deposited on the patterned Si3N4/STO at room temperature. The amorphous LAO epitaxially crystallized within the nanoscale-patterned holes with fully relaxed lattice parameters through solid phase epitaxy, resulting in the formation of nanoscale LAO/STO epitaxial heterostructures.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"10 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141171057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. E. Khokhlov, A. E. Dolgikh, B. A. Ivanov, A. V. Kimel
A pair of circularly polarized laser pulses of opposite helicities are shown to control the route of spin reorientation phase transition in the rare-earth antiferromagnetic orthoferrite (Sm0.55Tb0.45)FeO3. The route can be efficiently controlled by the delay between the pulses and the sample temperature. Simulations employing previously published models of laser-induced spin dynamics in orthoferrites failed to reproduce the experimental results. We suggest that the failure is due to neglected temperature dependence of the antiferromagnetic resonance damping in the material. Taking into account the experimentally deduced temperature dependence of the damping, we obtained good agreement between the simulations and the experiment.
{"title":"Double pulse all-optical coherent control of ultrafast spin-reorientation in an antiferromagnetic rare-earth orthoferrite","authors":"N. E. Khokhlov, A. E. Dolgikh, B. A. Ivanov, A. V. Kimel","doi":"10.1063/5.0197976","DOIUrl":"https://doi.org/10.1063/5.0197976","url":null,"abstract":"A pair of circularly polarized laser pulses of opposite helicities are shown to control the route of spin reorientation phase transition in the rare-earth antiferromagnetic orthoferrite (Sm0.55Tb0.45)FeO3. The route can be efficiently controlled by the delay between the pulses and the sample temperature. Simulations employing previously published models of laser-induced spin dynamics in orthoferrites failed to reproduce the experimental results. We suggest that the failure is due to neglected temperature dependence of the antiferromagnetic resonance damping in the material. Taking into account the experimentally deduced temperature dependence of the damping, we obtained good agreement between the simulations and the experiment.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"214 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ability of mechanical systems to perform basic computations has gained traction over recent years, providing an unconventional alternative to digital computing in off grid, low power, and severe environments, which render the majority of electronic components inoperable. However, much of the work in mechanical computing has focused on logic operations via quasi-static prescribed displacements in origami, bistable, and soft deformable matter. Here, we present a first attempt to describe the fundamental framework of an elastic neuromorphic metasurface that performs distinct classification tasks, providing a new set of challenges, given the complex nature of elastic waves with respect to scattering and manipulation. Multiple layers of reconfigurable waveguides are phase-trained via constant weights and trainable activation functions in a manner that enables the resultant wave scattering at the readout location to focus on the correct class within the detection plane. We further demonstrate the neuromorphic system’s reconfigurability in performing two distinct tasks, eliminating the need for costly remanufacturing.
{"title":"Mechanical intelligence via fully reconfigurable elastic neuromorphic metasurfaces","authors":"M. Moghaddaszadeh, M. Mousa, A. Aref, M. Nouh","doi":"10.1063/5.0201761","DOIUrl":"https://doi.org/10.1063/5.0201761","url":null,"abstract":"The ability of mechanical systems to perform basic computations has gained traction over recent years, providing an unconventional alternative to digital computing in off grid, low power, and severe environments, which render the majority of electronic components inoperable. However, much of the work in mechanical computing has focused on logic operations via quasi-static prescribed displacements in origami, bistable, and soft deformable matter. Here, we present a first attempt to describe the fundamental framework of an elastic neuromorphic metasurface that performs distinct classification tasks, providing a new set of challenges, given the complex nature of elastic waves with respect to scattering and manipulation. Multiple layers of reconfigurable waveguides are phase-trained via constant weights and trainable activation functions in a manner that enables the resultant wave scattering at the readout location to focus on the correct class within the detection plane. We further demonstrate the neuromorphic system’s reconfigurability in performing two distinct tasks, eliminating the need for costly remanufacturing.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"1 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141064080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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