APL MaterialsPub Date : 2024-08-30DOI: 10.1063/5.0221776
Jing Zhou, Lisen Huang, Sherry Lee Koon Yap, Dennis Jing Xiong Lin, Bingjin Chen, Shaohai Chen, Seng Kai Wong, Jinjun Qiu, James Lourembam, Anjan Soumyanarayanan, Sze Ter Lim
{"title":"Synergizing intrinsic symmetry breaking with spin–orbit torques for field-free perpendicular magnetic tunnel junction","authors":"Jing Zhou, Lisen Huang, Sherry Lee Koon Yap, Dennis Jing Xiong Lin, Bingjin Chen, Shaohai Chen, Seng Kai Wong, Jinjun Qiu, James Lourembam, Anjan Soumyanarayanan, Sze Ter Lim","doi":"10.1063/5.0221776","DOIUrl":"https://doi.org/10.1063/5.0221776","url":null,"abstract":"Current-induced spin–orbit torque (SOT) facilitates the ultrafast electrical manipulation of magnetic tunnel junction (MTJ), which is a leading non-volatile technology for the microelectronic industry. The key bottleneck to the commercial application of SOT-MTJ is the absence of a practicable symmetry-breaking scheme to switch perpendicular magnetization without an external magnetic field. Here, we demonstrate the wafer-scale realization of internalized field-free switching in perpendicular SOT-MTJ using conventional materials and device structure. We utilize a dual-function tungsten (W) spacer, which generates sizable SOT while concomitantly breaking symmetry via interlayer exchange coupling (IEC). Tuning the W thickness enables field-free switching with two types of IEC. An optimized combination of SOT and IEC ensures competitive switching performance, with our device exhibiting excellent thermal stability, low switching current density, and fast operating speed. This work builds the long-sought bridge between SOT manipulation of magnetization and wafer-scale field-free perpendicular MTJ. It underscores the urgent need to incorporate perpendicular SOT-MTJ in integrated circuits for applications in logic, memory, and unconventional computing.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"27 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197804","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}
{"title":"Unveiling charge transport in monolayer and few-layer CoPS3/metal contact: Insight from C-AFM","authors":"Mouhui Yan, Haotian Wang, Wenqi Wei, Tianxiang Zhu, Guanghui Cao, Jianxin Zhong, Wei Ren","doi":"10.1063/5.0222472","DOIUrl":"https://doi.org/10.1063/5.0222472","url":null,"abstract":"Monolayer and few-layer CoPS3 have been successfully synthesized via an Au-assisted exfoliation technique, with their transport properties subsequently investigated by conductive atomic force microscopy. Rectification effects can be observed in CoPS3 nanosheets due to the Schottky junction formation at the Au/CoPS3 interface, especially in configurations comprising two or more layer flakes. The distinct transport properties between monolayer and few-layer samples demonstrate that the charge transport behavior in the vertical direction is associated with the van der Waals gap. The calculated electron affinity for CoPS3 is about 4.84 eV, as revealed by the thermionic emission model. The results obtained contribute to the knowledge base concerning the transport characteristics of ultrathin MPX3, facilitating further exploration of the transport behavior of these materials and their potential applications in novel electronic devices.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"97 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197809","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}
APL MaterialsPub Date : 2024-08-23DOI: 10.1063/5.0228692
Xiangjun Liu, Yue Hu, Yikun Ju, Pu Yang, Naisi Shen, Anqi Yang, Rui Wu, Bairong Fang, Liangle Liu
{"title":"Immunomodulatory hydrogels for tissue repair and regeneration","authors":"Xiangjun Liu, Yue Hu, Yikun Ju, Pu Yang, Naisi Shen, Anqi Yang, Rui Wu, Bairong Fang, Liangle Liu","doi":"10.1063/5.0228692","DOIUrl":"https://doi.org/10.1063/5.0228692","url":null,"abstract":"Tissue repair and regeneration have long been a focus of research, with growing evidence highlighting the role played by immunomodulation. The repair of tissue cells can be significantly promoted through the localized immunomodulation of tissues. Hydrogels are increasingly used in this field due to their biocompatibility, versatility, and relative ease of fabrication. This Review highlights the critical role of inflammation and immune development in the complex process of tissue repair after injury, highlighting the dynamic interactions between immune cells that ultimately influence the outcome of tissue healing. We also summarize the precise functions of immune cells and their responses in various tissue injury scenarios, which are critical for harnessing the full potential of immunomodulatory strategies to promote tissue repair. We discuss recent advances in drug-carrying hydrogels, which offer promising avenues for tissue regeneration with precise control of the immune environment for constructive tissue repair. Further advances in our understanding of the mechanisms driving inflammation and immune cell behavior during tissue injury are expected to foster the development of increasingly effective hydrogel-based immunomodulatory strategies to promote tissue repair and regeneration.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"3 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197831","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}
{"title":"Enhancing terahertz magneto-optical effects in wafer-scale RIG single crystal thick films with anti-reflective coatings for improved transmittance","authors":"Qiang Xue, Yuan-Jing Zhang, Qing-Hui Yang, Huai-Wu Zhang, Qi-Ye Wen","doi":"10.1063/5.0219811","DOIUrl":"https://doi.org/10.1063/5.0219811","url":null,"abstract":"Wafer-scale rare-earth iron garnet (RIG) single crystal thick films were fabricated on 3-in. gadolinium gallium garnet (GGG) substrates using liquid phase epitaxy. The terahertz transmittance of the RIG crystals improved after removing the GGG substrate by polishing. The time-domain spectra at Terahertz (THz) frequencies indicate the existence of a magneto-optical effect in RIG samples. The results indicate that the RIG samples exhibit a high refractive index of ∼4.50 within the 0.1–1.0 THz frequency range, a transmittance of around 40%, and an absorption rate of only 10–50 cm−1. The Faraday rotation angles of the thick single-crystal films of the RIG samples were measured using a THz-TDS system. The RIG has a thickness of ∼330 μm. The Faraday rotation angles of RIG crystals at THz frequencies can reach up to 16° when an external magnetic field of 0.18 T is applied. The Verdet constants of the RIG sample were calculated to be ∼120°/mm/T. To improve the transmittance of the RIG sample, epoxy resin and polymethylpentene (TPX) were used as anti-reflective films. The transmittance of the RIG sample increased by ∼5% for the 80 μm thick epoxy and about 10% for the 320 μm thick TPX. Therefore, this RIG single crystal thick film can achieve a low loss, a high transmittance, and a strong magneto-optical effect in the terahertz region with the cooperation of a reflection-reducing film. It is expected to have wide applications in terahertz magnetic polarization conversion, non-reciprocal phase shifters, and isolators.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"71 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197823","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}
APL MaterialsPub Date : 2024-08-19DOI: 10.1063/5.0221334
Lucia Varbaro, Lukas Korosec, Chih-Ying Hsu, Duncan T. L. Alexander, Nicolas Jaouen, Jean-Marc Triscone
{"title":"Role of the coupling of the electronic transitions on the order of the metal-to-insulator phase transition in nickelates","authors":"Lucia Varbaro, Lukas Korosec, Chih-Ying Hsu, Duncan T. L. Alexander, Nicolas Jaouen, Jean-Marc Triscone","doi":"10.1063/5.0221334","DOIUrl":"https://doi.org/10.1063/5.0221334","url":null,"abstract":"Rare-earth nickelates (chemical formula RNiO3, R being a rare-earth cation) display a temperature-dependent metal-to-insulator transition (MIT) together with a breathing distortion of the NiO6 octahedra units at a temperature ranging from 0 to 600 K depending on the size of the R cation. Their rich phase diagram is also characterized by a paramagnetic to antiferromagnetic transition that occurs at the same temperature as the MIT for R = Pr, Nd, while it arises at lower temperatures for all the other members of the series. In this work, we have investigated the order of the MIT in a portion of the phase diagram spanning from SmNiO3 to NdNiO3 by means of temperature dependent transport measurements and resonant elastic x-ray scattering performed on high quality epitaxial SmxNd1−xNiO3 solid solution thin films. Our results show that the order of the metal-to-insulator transition does not depend on whether or not the MIT is coupled with the magnetic transition.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"137 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197810","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}
APL MaterialsPub Date : 2024-08-15DOI: 10.1063/5.0217540
Qi Song, Zhiren He, Brendan D. Faeth, Christopher T. Parzyck, Anna Scheid, Chad J. Mowers, Yufan Feng, Qing Xu, Sonia Hasko, Jisung Park, Matthew R. Barone, Y. Eren Suyolcu, Peter A. van Aken, Betül Pamuk, Craig J. Fennie, Phil D. C. King, Kyle M. Shen, Darrell G. Schlom
{"title":"Surface reconstructions and electronic structure of metallic delafossite thin films","authors":"Qi Song, Zhiren He, Brendan D. Faeth, Christopher T. Parzyck, Anna Scheid, Chad J. Mowers, Yufan Feng, Qing Xu, Sonia Hasko, Jisung Park, Matthew R. Barone, Y. Eren Suyolcu, Peter A. van Aken, Betül Pamuk, Craig J. Fennie, Phil D. C. King, Kyle M. Shen, Darrell G. Schlom","doi":"10.1063/5.0217540","DOIUrl":"https://doi.org/10.1063/5.0217540","url":null,"abstract":"The growing interest in the growth and study of thin films of low-dimensional metallic delafossites, with the general formula ABO2, is driven by their potential to exhibit electronic and magnetic characteristics that are not accessible in bulk systems. The layered structure of these compounds introduces unique surface states as well as electronic and structural reconstructions, making the investigation of their surface behavior pivotal to understanding their intrinsic electronic structure. In this work, we study the surface phenomena of epitaxially grown PtCoO2, PdCoO2, and PdCrO2 films, utilizing a combination of molecular-beam epitaxy and angle-resolved photoemission spectroscopy. Through precise control of surface termination and treatment, we discover a pronounced 3×3 surface reconstruction in PtCoO2 films and PdCoO2 films, alongside a 2 × 2 surface reconstruction observed in PdCrO2 films. These reconstructions have not been reported in prior studies of delafossites. Furthermore, our computational investigations demonstrate the BO2 surface’s relative stability compared to the A-terminated surface and the significant reduction in surface energy facilitated by the reconstruction of the A-terminated surface. These experimental and theoretical insights illuminate the complex surface dynamics in metallic delafossites, paving the way for future explorations of their distinctive properties in low-dimensional studies.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"45 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197825","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}
APL MaterialsPub Date : 2024-08-15DOI: 10.1063/5.0222154
Yukun Teng, Guangcun Shan
{"title":"Interpretable machine learning for materials discovery: Predicting CO2 adsorption properties of metal–organic frameworks","authors":"Yukun Teng, Guangcun Shan","doi":"10.1063/5.0222154","DOIUrl":"https://doi.org/10.1063/5.0222154","url":null,"abstract":"Metal–organic frameworks (MOFs), as novel porous crystalline materials with high porosity and a large specific surface area, have been increasingly utilized for CO2 adsorption. Machine learning (ML) combined with molecular simulations is used to identify MOFs with high CO2 adsorption capacity from millions of MOF structures. In this study, 23 structural and molecular features and 765 calculated features were proposed for the ML model and trained on a hypothetical MOF dataset for CO2 adsorption at different pressures. The calculated features improved the prediction accuracy of the ML model by 15%–20% and revealed its interpretability, consistent with the analysis of the interaction potential. Subsequently, the importance of the relevant features was ranked at different pressures. Regardless of the pressure, the molecular structure and pore size were the most critical factors. van der Waals force-related descriptors gained more competitive advantages at low pressures, whereas electrical-field-related descriptors gradually dominated at high pressures. Overall, this study provides a novel perspective to guide the initial high-throughput screening of MOFs as high-performance CO2 adsorption materials.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"30 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197826","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}
{"title":"Room temperature chiral magnetoresistance in a chiral-perovskite-based perpendicular spin valve","authors":"Min-Gu Kang, In-Kook Hwang, Hee-Chang Kyung, Jaimin Kang, Donghyeon Han, Soogil Lee, Junyoung Kwon, Kyung-Jin Lee, Jihyeon Yeom, Byong-Guk Park","doi":"10.1063/5.0221834","DOIUrl":"https://doi.org/10.1063/5.0221834","url":null,"abstract":"Chirality-induced spin selectivity (CISS) allows for the generation of spin currents without the need for ferromagnets or external magnetic fields, enabling innovative spintronic device designs. One example is a chiral spin valve composed of ferromagnetic and chiral materials, in which the resistance depends on both the magnetization direction of the ferromagnet and the chirality of the chiral material. So far, chiral spin valves have predominately employed chiral organic molecules, which have limited device applications. Chiral perovskites, which combine the properties of inorganic perovskites with chiral organic molecules, provide an excellent platform for exploring CISS-based devices. However, previous chiral perovskite-based spin valves exhibited magnetoresistance (MR) only at low temperatures. Here, we report room temperature MR in a chiral spin valve consisting of chiral perovskites/AlOx/perpendicular ferromagnet structures. It is observed that the chiral MR increases with rising temperature, suggesting the crucial role of phonon-induced enhancement of spin–orbit coupling in CISS in our device. Furthermore, we enhanced the chiral MR by introducing chiral molecules with amplified chirality. This highlights the potential of chirality engineering to improve CISS and the associated chiral MR, thereby opening possibilities for chiral spin valves tailored for cutting-edge spintronic applications.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"62 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225268","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}
{"title":"Elastocaloric effect and cooling performance of NiTi sheets in a continuous rotating bending elastocaloric cooler","authors":"Siyuan Cheng, Wanju Sun, Xueshi Li, Jiongjiong Zhang","doi":"10.1063/5.0217563","DOIUrl":"https://doi.org/10.1063/5.0217563","url":null,"abstract":"Elastocaloric cooling technology has the prospect of becoming a commercialized green alternative to current vapor-compression technology, and the systematic characterization of the elastocaloric effect and microstructure has become increasingly significant for the optimization of elastocaloric coolers and heat pumps. In this work, a comprehensive elastocaloric effect characterization for a dog-bone shaped NiTi sheet with a thickness of 0.5 mm was performed for the application in a compact continuous rotating bending elastocaloric cooler. The elastocaloric effect was found to be nearly identical under Brayton-like and sinusoidal force-controlled cyclic tensile loadings. The maximum adiabatic temperature change values of 31 and 23 K were recorded in Brayton-like cyclic loadings under maximum applied stress of 600 and 400 MPa, respectively, with an applied strain rate of 0.1 s−1. During fatigue tests, large applied stress (>600 MPa) and high applied strain rates (>0.1 s−1) tended to result in premature failure of the NiTi sheet samples. In the continuous rotating bending elastocaloric cooler, the sheets generated a temperature span of 6 K between the copper heat sink and heat source. The results of this work provide a set of thermophysical property data for the elastocaloric solid refrigerant and insights for the optimization of structural and operational parameters in elastocaloric coolers and heat pumps.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"77 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197822","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}
APL MaterialsPub Date : 2024-08-14DOI: 10.1063/5.0222618
Panpan Li, Jacob Ewing, Matthew S. Wong, Yifan Yao, Hongjian Li, Srinivas Gandrothula, Jordan M. Smith, Mike Iza, Shuji Nakamura, Steven P. DenBaars
{"title":"Advances in InGaN-based RGB micro-light-emitting diodes for AR applications: Status and perspective","authors":"Panpan Li, Jacob Ewing, Matthew S. Wong, Yifan Yao, Hongjian Li, Srinivas Gandrothula, Jordan M. Smith, Mike Iza, Shuji Nakamura, Steven P. DenBaars","doi":"10.1063/5.0222618","DOIUrl":"https://doi.org/10.1063/5.0222618","url":null,"abstract":"Micro-light-emitting diodes (µLEDs) are gathering significant interest as a technology for emerging micro-displays. However, µLEDs encounter numerous obstacles, including size-dependent efficiency loss, poor efficiency of red µLEDs, and challenges associated with the mass transfer and integration of full-color µLEDs. These issues become more acute in ultra-small µLEDs (<5 µm), which were required by the augmented reality (AR) displays. Here, we discuss the principal challenges faced by µLEDs and explore the possible solutions. We highlight recent advances in InGaN-based RGB µLEDs tailored for AR displays. In particular, we discuss the advancements in ultra-small InGaN µLEDs scaled down to 1 µm, the developments in InGaN red µLEDs, and the implementation of tunnel junction-based cascaded InGaN µLEDs for monolithic integration.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"14 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197828","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}