Pub Date : 2024-11-15DOI: 10.1038/s43246-024-00635-9
Manabu Sato, Juba Bouaziz, Shuntaro Sumita, Shingo Kobayashi, Ikuma Tateishi, Stefan Blügel, Akira Furusaki, Motoaki Hirayama
Topological semimetals, known for their intriguing properties arising from band degeneracies, have garnered significant attention. However, the discovery of a material realization and the detailed characterization of spinless Dirac semimetals have not yet been accomplished. Here, we propose from first-principles calculations that the RE8CoX3 group (RE = rare earth elements, X = Al, Ga, or In) contains ideal spinless Dirac semimetals whose Fermi surfaces are fourfold degenerate band-crossing points (without including spin degeneracy). Despite the lack of space inversion symmetry in these materials, Dirac points are formed on the rotation-symmetry axis due to accidental degeneracies of two bands corresponding to different 2-dimensional irreducible representations of the C6v group. We also investigate, through first-principles calculations and effective model analysis, various phase transitions caused by lattice distortion or elemental substitutions from the Dirac semimetal phase to distinct topological semimetallic phases such as nonmagnetic linked-nodal-line and Weyl semimetals (characterized by the second Stiefel–Whitney class) and ferromagnetic Weyl semimetals. Band degeneracies at the Fermi level in topological semimetals are sources of intriguing interference effects between electronic states around the degeneracy points. Here, the RE8CoX3 compounds, with RE = rare-earth and X = Al, Ga, or In, are proposed as realizations of ideal spinless Dirac semimetals hosting the fourfold degenerate band-crossing points without the spin degrees of freedom.
{"title":"Ideal spin-orbit-free Dirac semimetal and diverse topological transitions in Y8CoIn3 family","authors":"Manabu Sato, Juba Bouaziz, Shuntaro Sumita, Shingo Kobayashi, Ikuma Tateishi, Stefan Blügel, Akira Furusaki, Motoaki Hirayama","doi":"10.1038/s43246-024-00635-9","DOIUrl":"10.1038/s43246-024-00635-9","url":null,"abstract":"Topological semimetals, known for their intriguing properties arising from band degeneracies, have garnered significant attention. However, the discovery of a material realization and the detailed characterization of spinless Dirac semimetals have not yet been accomplished. Here, we propose from first-principles calculations that the RE8CoX3 group (RE = rare earth elements, X = Al, Ga, or In) contains ideal spinless Dirac semimetals whose Fermi surfaces are fourfold degenerate band-crossing points (without including spin degeneracy). Despite the lack of space inversion symmetry in these materials, Dirac points are formed on the rotation-symmetry axis due to accidental degeneracies of two bands corresponding to different 2-dimensional irreducible representations of the C6v group. We also investigate, through first-principles calculations and effective model analysis, various phase transitions caused by lattice distortion or elemental substitutions from the Dirac semimetal phase to distinct topological semimetallic phases such as nonmagnetic linked-nodal-line and Weyl semimetals (characterized by the second Stiefel–Whitney class) and ferromagnetic Weyl semimetals. Band degeneracies at the Fermi level in topological semimetals are sources of intriguing interference effects between electronic states around the degeneracy points. Here, the RE8CoX3 compounds, with RE = rare-earth and X = Al, Ga, or In, are proposed as realizations of ideal spinless Dirac semimetals hosting the fourfold degenerate band-crossing points without the spin degrees of freedom.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-10"},"PeriodicalIF":7.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00635-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-15DOI: 10.1038/s43246-024-00693-z
Daniele Perilli, Sonia Freddi, Michele Zanotti, Giovanni Drera, Andrea Casotto, Stefania Pagliara, Luca Schio, Luigi Sangaletti, Cristiana Di Valentin
Highly sensitive and selective gas-sensing materials are critical for applications ranging from environmental monitoring to breath analysis. A rational approach at the nanoscale is urgent to design next-generation sensing devices. In previous work, we unveiled interesting charge transfer channels at the interface between p-type doped graphene and a layer of nickel phthalocyanine (NiPc) molecules, which we believe could be successfully exploited in gas sensing devices. Here, we have investigated the graphene-NiPc interface’s response to adsorbed gas molecules via first-principles calculations. We focused on NH3 and NO2 as test molecules, representing electron donors and acceptors, respectively. Notably, we identified the Ni dz2 orbital as a key player in mediating the charge transfer and affecting the charge carrier density in graphene. As a proof-of-concept, we then prepared the graphene-NiPc system as a chemiresistor device and exposed it to NH3 and NO2 at room temperature. The sensing tests revealed excellent sensitivity and selectivity, along with a rapid recovery time and a remarkably low detection limit. Highly sensitive and selective gas-sensing materials are important for applications ranging from environmental monitoring to breath analysis. Here, the gas sensing response of the heterointerface between graphene and nickel phthalocyanine is investigated by first-principles calculations and tested in a chemiresistor device exposed to NH3 and NO2 at room temperature.
高灵敏度和高选择性的气体传感材料对于从环境监测到呼吸分析等各种应用都至关重要。要设计下一代传感设备，迫切需要在纳米尺度上采用合理的方法。在之前的工作中，我们揭示了 p 型掺杂石墨烯和酞菁镍（NiPc）分子层界面上有趣的电荷转移通道，我们相信气体传感设备可以成功利用这些通道。在此，我们通过第一原理计算研究了石墨烯-酞菁镍分子界面对吸附气体分子的响应。我们将 NH3 和 NO2 作为测试分子，分别代表电子供体和受体。值得注意的是，我们发现 Ni dz2 轨道是介导电荷转移和影响石墨烯中电荷载流子密度的关键因素。作为概念验证，我们随后将石墨烯-NiPc 系统制备成化学电阻器装置，并在室温下将其暴露于 NH3 和 NO2 中。传感测试表明，该系统具有出色的灵敏度和选择性、快速恢复时间和极低的检测限。高灵敏度和高选择性的气体传感材料对于从环境监测到呼吸分析等各种应用都非常重要。本文通过第一原理计算研究了石墨烯与酞菁镍之间异质界面的气体传感响应，并在室温下暴露于 NH3 和 NO2 的化学电阻器装置中进行了测试。
{"title":"Design of highly responsive chemiresistor-based sensors by interfacing NiPc with graphene","authors":"Daniele Perilli, Sonia Freddi, Michele Zanotti, Giovanni Drera, Andrea Casotto, Stefania Pagliara, Luca Schio, Luigi Sangaletti, Cristiana Di Valentin","doi":"10.1038/s43246-024-00693-z","DOIUrl":"10.1038/s43246-024-00693-z","url":null,"abstract":"Highly sensitive and selective gas-sensing materials are critical for applications ranging from environmental monitoring to breath analysis. A rational approach at the nanoscale is urgent to design next-generation sensing devices. In previous work, we unveiled interesting charge transfer channels at the interface between p-type doped graphene and a layer of nickel phthalocyanine (NiPc) molecules, which we believe could be successfully exploited in gas sensing devices. Here, we have investigated the graphene-NiPc interface’s response to adsorbed gas molecules via first-principles calculations. We focused on NH3 and NO2 as test molecules, representing electron donors and acceptors, respectively. Notably, we identified the Ni dz2 orbital as a key player in mediating the charge transfer and affecting the charge carrier density in graphene. As a proof-of-concept, we then prepared the graphene-NiPc system as a chemiresistor device and exposed it to NH3 and NO2 at room temperature. The sensing tests revealed excellent sensitivity and selectivity, along with a rapid recovery time and a remarkably low detection limit. Highly sensitive and selective gas-sensing materials are important for applications ranging from environmental monitoring to breath analysis. Here, the gas sensing response of the heterointerface between graphene and nickel phthalocyanine is investigated by first-principles calculations and tested in a chemiresistor device exposed to NH3 and NO2 at room temperature.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-13"},"PeriodicalIF":7.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00693-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1038/s43246-024-00679-x
Jan Hrabovsky, Miroslav Kucera, Lucie Palousova, Jakub Zazvorka, Jan Kubat, Lei Bi, Martin Veis
Doping of luminescent materials by rare-earth ions is common practice to achieve desired emission properties for a large variety of applications. As several rare-earths ions are frequently combined, it is subsequently difficult to effectively detect and control their homogeneous distribution within the host material. Here, we present a simple, rapid, large scale and precise method of rare-earth mapping using a commercial UV-Vis scanner. We discuss the influence of rare-earth distribution on the physical, optical and luminescent properties with no observable qualitative effect on photoluminescent properties and optical anisotropy. On the contrary, rare-earth-rich areas exhibit significantly higher values of refractive index and optical absorption, which allowed for their identification by the commercial scanner device. The presented method thus provides fast and accurate information about the rare-earth distribution in the material volume with high resolution (≈2.7 µm) and low limit of concentration difference detection (≈0.014 at.%) compared to other techniques, which makes it a promising candidate for high throughput measurements. Mapping the distributions of various rare-earth dopants when combined within a host material is challenging, Here, a fast and precise approach to mapping rare-earth doping distribution based on a commercial UV-Vis scanner shows that dopants locally modify the optical properties of the material.
{"title":"Rapid and precise large area mapping of rare-earth doping homogeneity in luminescent materials","authors":"Jan Hrabovsky, Miroslav Kucera, Lucie Palousova, Jakub Zazvorka, Jan Kubat, Lei Bi, Martin Veis","doi":"10.1038/s43246-024-00679-x","DOIUrl":"10.1038/s43246-024-00679-x","url":null,"abstract":"Doping of luminescent materials by rare-earth ions is common practice to achieve desired emission properties for a large variety of applications. As several rare-earths ions are frequently combined, it is subsequently difficult to effectively detect and control their homogeneous distribution within the host material. Here, we present a simple, rapid, large scale and precise method of rare-earth mapping using a commercial UV-Vis scanner. We discuss the influence of rare-earth distribution on the physical, optical and luminescent properties with no observable qualitative effect on photoluminescent properties and optical anisotropy. On the contrary, rare-earth-rich areas exhibit significantly higher values of refractive index and optical absorption, which allowed for their identification by the commercial scanner device. The presented method thus provides fast and accurate information about the rare-earth distribution in the material volume with high resolution (≈2.7 µm) and low limit of concentration difference detection (≈0.014 at.%) compared to other techniques, which makes it a promising candidate for high throughput measurements. Mapping the distributions of various rare-earth dopants when combined within a host material is challenging, Here, a fast and precise approach to mapping rare-earth doping distribution based on a commercial UV-Vis scanner shows that dopants locally modify the optical properties of the material.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-9"},"PeriodicalIF":7.5,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00679-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1038/s43246-024-00696-w
Aldo Isidori
Combining in-memory sensing and computing is key to the realization of machine vision systems in artificial intelligence applications. Now, non-volatile magnetic memory and optical sensing capabilities are integrated in two-dimensional Fe3GaTe2/WSe2/Fe3GaTe2 junctions operating at room temperature.
{"title":"Machine vision system by optically tunable 2D magnetic junctions","authors":"Aldo Isidori","doi":"10.1038/s43246-024-00696-w","DOIUrl":"10.1038/s43246-024-00696-w","url":null,"abstract":"Combining in-memory sensing and computing is key to the realization of machine vision systems in artificial intelligence applications. Now, non-volatile magnetic memory and optical sensing capabilities are integrated in two-dimensional Fe3GaTe2/WSe2/Fe3GaTe2 junctions operating at room temperature.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-2"},"PeriodicalIF":7.5,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00696-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-11DOI: 10.1038/s43246-024-00694-y
Ji-Ho Park, Min Tae Park, Geon-Woo Baek, Shin-ichi Kimura, Myung-Hwa Jung, Kab-Jin Kim
Phase-changing materials have been a cornerstone of condensed matter physics for decades. A quintessential example is iron-rhodium (FeRh), which undergoes a first-order phase transition from antiferromagnetic to ferromagnetic states near room temperature. The pivotal aspect of this transition is a marked alteration in electrical conductivity. However, its underlying origin still remains elusive, largely due to the difficulties of directly probing fundamental transport during this phase transition. In this study, we investigate the fundamentals of FeRh’s electrical transport employing terahertz time-domain spectroscopy (THz-TDS). Leveraging the Drude model, we discerned the distinct contributions of extrinsic (momentum scattering time, τ) and intrinsic (charge density, n, and effective mass, m*) factors to electrical conductivity independently. Notably, our investigation unveiled a sharp alteration in n and m* during the phase transition, contrasting with the gradual monotonic decrease of τ with rising temperature. Consequently, our findings provide compelling evidence that the conductivity change in FeRh during the phase transition originates from a restructuring of its band structure. This work provides a crucial step towards a comprehensive understanding of the electrical transport changes occurring during the phase transition, offering valuable insights into the behaviour of phase changing materials. Phase-changing materials such as FeRh, undergoing a first-order phase transition from antiferromagnetic to ferromagnetic near room temperature, are attractive for various applications. Here, terahertz time-domain spectroscopy provides evidence that the conductivity change in FeRh during the phase transition originates from a restructuring of its band structure.
{"title":"Unraveling the origin of conductivity change in Co-doped FeRh phase transition","authors":"Ji-Ho Park, Min Tae Park, Geon-Woo Baek, Shin-ichi Kimura, Myung-Hwa Jung, Kab-Jin Kim","doi":"10.1038/s43246-024-00694-y","DOIUrl":"10.1038/s43246-024-00694-y","url":null,"abstract":"Phase-changing materials have been a cornerstone of condensed matter physics for decades. A quintessential example is iron-rhodium (FeRh), which undergoes a first-order phase transition from antiferromagnetic to ferromagnetic states near room temperature. The pivotal aspect of this transition is a marked alteration in electrical conductivity. However, its underlying origin still remains elusive, largely due to the difficulties of directly probing fundamental transport during this phase transition. In this study, we investigate the fundamentals of FeRh’s electrical transport employing terahertz time-domain spectroscopy (THz-TDS). Leveraging the Drude model, we discerned the distinct contributions of extrinsic (momentum scattering time, τ) and intrinsic (charge density, n, and effective mass, m*) factors to electrical conductivity independently. Notably, our investigation unveiled a sharp alteration in n and m* during the phase transition, contrasting with the gradual monotonic decrease of τ with rising temperature. Consequently, our findings provide compelling evidence that the conductivity change in FeRh during the phase transition originates from a restructuring of its band structure. This work provides a crucial step towards a comprehensive understanding of the electrical transport changes occurring during the phase transition, offering valuable insights into the behaviour of phase changing materials. Phase-changing materials such as FeRh, undergoing a first-order phase transition from antiferromagnetic to ferromagnetic near room temperature, are attractive for various applications. Here, terahertz time-domain spectroscopy provides evidence that the conductivity change in FeRh during the phase transition originates from a restructuring of its band structure.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-7"},"PeriodicalIF":7.5,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00694-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1038/s43246-024-00680-4
Bradley Napier, Giusy Matzeu, Fiorenzo G. Omenetto
Textile integrated sensors based on conductive, electrochemically active microfibers can enable inexpensive, nearly invisible distributed sensing of sweat in clothing. Reduced graphene oxide fibers are mechanically robust, conductive, and can be easily functionalized to form a variety of sensors with properties comparable to planar fabricated sensors, given their ability to work both as electrical interconnections and as a base electrode. Here, we present an electrochemical yarn based on modified dry-spun reduced graphene oxide fibers. This braided format contains reference, counter electrode, a lactate-responsive fiber functionalized with lactate oxidase, and a pH-sensing fiber for calibration in a single, robust, weavable format. This electrochemical yarn was integrated into a demonstrator wearable textile-patch capable of continuous data collection and wireless data transmitted to an ad-hoc app. The yarns perform comparably to traditional probes in a format of broad utility for standalone or integrated monitoring of physiological parameters. Textile-based sweat sensors offer the possibility of low-cost health monitoring. Here, an electrochemical yarn based on reduced-graphene oxide is integrated into a textile patch that continuously collects physiological data and wirelessly sends it to an app.
{"title":"Multi-sensing yarns for continuous wireless sweat lactate monitoring","authors":"Bradley Napier, Giusy Matzeu, Fiorenzo G. Omenetto","doi":"10.1038/s43246-024-00680-4","DOIUrl":"10.1038/s43246-024-00680-4","url":null,"abstract":"Textile integrated sensors based on conductive, electrochemically active microfibers can enable inexpensive, nearly invisible distributed sensing of sweat in clothing. Reduced graphene oxide fibers are mechanically robust, conductive, and can be easily functionalized to form a variety of sensors with properties comparable to planar fabricated sensors, given their ability to work both as electrical interconnections and as a base electrode. Here, we present an electrochemical yarn based on modified dry-spun reduced graphene oxide fibers. This braided format contains reference, counter electrode, a lactate-responsive fiber functionalized with lactate oxidase, and a pH-sensing fiber for calibration in a single, robust, weavable format. This electrochemical yarn was integrated into a demonstrator wearable textile-patch capable of continuous data collection and wireless data transmitted to an ad-hoc app. The yarns perform comparably to traditional probes in a format of broad utility for standalone or integrated monitoring of physiological parameters. Textile-based sweat sensors offer the possibility of low-cost health monitoring. Here, an electrochemical yarn based on reduced-graphene oxide is integrated into a textile patch that continuously collects physiological data and wirelessly sends it to an app.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-8"},"PeriodicalIF":7.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00680-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1038/s43246-024-00691-1
N. S. Portillo-Vélez, Juan L. Obeso, José Antonio de los Reyes, Ricardo A. Peralta, Ilich A. Ibarra, Michael T. Huxley
Defect engineering has developed over the last decade to become an inimitable tool with which to shape Metal-Organic Framework (MOF) chemistry; part of an evolution in the perception of MOFs from perfect, rigid matrices to dynamic materials whose chemistry is shaped as much by imperfections as it is by their molecular components. However, challenges in defect characterisation and reproducibility persist and, coupled with an as-yet opaque role for synthetic parameters in defect formation, deny chemists the full potential of reticular synthesis. Herein we map the broad implications defects have on MOF properties, highlight key challenges and explore the remarkable ways imperfection enriches MOF chemistry. Engineering defects into metal-organic frameworks is a strategy to grant additional properties but there are still challenges with their reproducibility. Here, this Perspective presents the benefits of defects in metal-organic framework properties and key challenges in the field.
{"title":"Benefits and complexity of defects in metal-organic frameworks","authors":"N. S. Portillo-Vélez, Juan L. Obeso, José Antonio de los Reyes, Ricardo A. Peralta, Ilich A. Ibarra, Michael T. Huxley","doi":"10.1038/s43246-024-00691-1","DOIUrl":"10.1038/s43246-024-00691-1","url":null,"abstract":"Defect engineering has developed over the last decade to become an inimitable tool with which to shape Metal-Organic Framework (MOF) chemistry; part of an evolution in the perception of MOFs from perfect, rigid matrices to dynamic materials whose chemistry is shaped as much by imperfections as it is by their molecular components. However, challenges in defect characterisation and reproducibility persist and, coupled with an as-yet opaque role for synthetic parameters in defect formation, deny chemists the full potential of reticular synthesis. Herein we map the broad implications defects have on MOF properties, highlight key challenges and explore the remarkable ways imperfection enriches MOF chemistry. Engineering defects into metal-organic frameworks is a strategy to grant additional properties but there are still challenges with their reproducibility. Here, this Perspective presents the benefits of defects in metal-organic framework properties and key challenges in the field.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-15"},"PeriodicalIF":7.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00691-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1038/s43246-024-00689-9
Hubert Dawczak-Dębicki, M. Victoria Ale Crivillero, Matthew S. Cook, Sean M. Thomas, Priscila F. S. Rosa, Jens Müller, Ulrich K. Rößler, Pedro Schlottmann, Steffen Wirth
Materials exhibiting electronic inhomogeneities at the nanometer scale have enormous potential for applications. Magnetic polarons are one such type of inhomogeneity which link the electronic, magnetic and lattice degrees of freedom in correlated matter and often give rise to colossal magnetoresistance. Here, we investigate single crystals of Eu5In2Sb6 by thermal expansion and magnetostriction along different crystallographic directions. These data provide compelling evidence for the formation of magnetic polarons in Eu5In2Sb6 well above the magnetic ordering temperature. More specifically, our results are consistent with anisotropic polarons with varying extent along the different crystallographic directions. A crossover revealed within the magnetically ordered phase can be associated with a surprising stabilization of ferromagnetic polarons within the global antiferromagnetic order upon decreasing temperature. These findings make Eu5In2Sb6 a rare example of such coexisting and competing magnetic orders and, importantly, shed new light on colossal magnetoresistive behavior beyond manganites. Materials exhibiting electronic inhomogeneities at the nanometer scale, such as magnetic polarons, have great potential for magnetoresistive applications. Here, thermal expansion and magnetostriction measurements on Eu5In2Sb6 single crystals reveal the formation of magnetic polarons well above the magnetic ordering temperature, providing insights on colossal magnetoresistive behavior beyond manganites.
{"title":"Thermodynamic evidence for polaron stabilization inside the antiferromagnetic order of Eu5In2Sb6","authors":"Hubert Dawczak-Dębicki, M. Victoria Ale Crivillero, Matthew S. Cook, Sean M. Thomas, Priscila F. S. Rosa, Jens Müller, Ulrich K. Rößler, Pedro Schlottmann, Steffen Wirth","doi":"10.1038/s43246-024-00689-9","DOIUrl":"10.1038/s43246-024-00689-9","url":null,"abstract":"Materials exhibiting electronic inhomogeneities at the nanometer scale have enormous potential for applications. Magnetic polarons are one such type of inhomogeneity which link the electronic, magnetic and lattice degrees of freedom in correlated matter and often give rise to colossal magnetoresistance. Here, we investigate single crystals of Eu5In2Sb6 by thermal expansion and magnetostriction along different crystallographic directions. These data provide compelling evidence for the formation of magnetic polarons in Eu5In2Sb6 well above the magnetic ordering temperature. More specifically, our results are consistent with anisotropic polarons with varying extent along the different crystallographic directions. A crossover revealed within the magnetically ordered phase can be associated with a surprising stabilization of ferromagnetic polarons within the global antiferromagnetic order upon decreasing temperature. These findings make Eu5In2Sb6 a rare example of such coexisting and competing magnetic orders and, importantly, shed new light on colossal magnetoresistive behavior beyond manganites. Materials exhibiting electronic inhomogeneities at the nanometer scale, such as magnetic polarons, have great potential for magnetoresistive applications. Here, thermal expansion and magnetostriction measurements on Eu5In2Sb6 single crystals reveal the formation of magnetic polarons well above the magnetic ordering temperature, providing insights on colossal magnetoresistive behavior beyond manganites.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-8"},"PeriodicalIF":7.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00689-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biopolymer research has led to the development of novel products through innovative strategies. Their functionalization is typically achieved by physical/chemical methods that require harsh chemicals or mechanical treatments. These functionalities could be alternatively achieved by employing bioengineering design methods. We demonstrate, a bioengineered dual-microbial approach to create functional bacterial cellulose from microbial workhorses. Komagataeibacter hansenii ATCC 53582 is used to produce bacterial cellulose and engineered E. coli is used to functionalize the matrix with a recombinant fibrous protein. The E. coli harbours synthetic genes for the secretion of amyloid curli protein subunit (CsgA) tagged with short functional M6A peptide domains. The incorporation of M6A-functionalized amyloid proteins into bacterial cellulose facilitates magnetite nanoparticle nucleation. We achieved a saturation magnetization of 40 emu g−1, a three-fold increase compared to existing strategies. The magnetic bacterial cellulose films demonstrate cytocompatibility and accelerate cell migration in the presence of magnetic field. Microbes have been shown to be effective for synthesizing functional materials. Here, bacterial cellulose is created via a dual microbial approach, with magnetite nanoparticles used to enhance magnetic behavior.
{"title":"Bioengineering approach for the design of magnetic bacterial cellulose membranes","authors":"Sundaravadanam Vishnu Vadanan, Rupali Reddy Pasula, Neel Joshi, Sierin Lim","doi":"10.1038/s43246-024-00562-9","DOIUrl":"10.1038/s43246-024-00562-9","url":null,"abstract":"Biopolymer research has led to the development of novel products through innovative strategies. Their functionalization is typically achieved by physical/chemical methods that require harsh chemicals or mechanical treatments. These functionalities could be alternatively achieved by employing bioengineering design methods. We demonstrate, a bioengineered dual-microbial approach to create functional bacterial cellulose from microbial workhorses. Komagataeibacter hansenii ATCC 53582 is used to produce bacterial cellulose and engineered E. coli is used to functionalize the matrix with a recombinant fibrous protein. The E. coli harbours synthetic genes for the secretion of amyloid curli protein subunit (CsgA) tagged with short functional M6A peptide domains. The incorporation of M6A-functionalized amyloid proteins into bacterial cellulose facilitates magnetite nanoparticle nucleation. We achieved a saturation magnetization of 40 emu g−1, a three-fold increase compared to existing strategies. The magnetic bacterial cellulose films demonstrate cytocompatibility and accelerate cell migration in the presence of magnetic field. Microbes have been shown to be effective for synthesizing functional materials. Here, bacterial cellulose is created via a dual microbial approach, with magnetite nanoparticles used to enhance magnetic behavior.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-9"},"PeriodicalIF":7.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00562-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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