Pub Date : 2024-08-12DOI: 10.1038/s41699-024-00492-7
Matthew D. Watson, Swagata Acharya, James E. Nunn, Laxman Nagireddy, Dimitar Pashov, Malte Rösner, Mark van Schilfgaarde, Neil R. Wilson, Cephise Cacho
We present the evolution of the electronic structure of CrSBr from its antiferromagnetic ground state to the paramagnetic phase above TN = 132 K, in both experiment and theory. Low-temperature angle-resolved photoemission spectroscopy (ARPES) results are obtained using a novel method to overcome sample charging issues, revealing quasi-2D valence bands in the ground state. The results are very well reproduced by our $${rm{QSG}}hat{{rm{W}}}$$ calculations, which further identify certain bands at the X points to be exchange-split pairs of states with mainly Br and S character. By tracing band positions as a function of temperature, we show the splitting disappears above TN. The energy splitting is interpreted as an effective exchange splitting in individual layers in which the Cr moments all align, within the so-called A-type antiferromagnetic arrangement. Our results lay firm foundations for the interpretation of the many other intriguing physical and optical properties of CrSBr.
我们从实验和理论两方面介绍了 CrSBr 在 TN = 132 K 以上从反铁磁基态到顺磁相的电子结构演变。低温角分辨光发射光谱（ARPES）采用一种新方法克服了样品充电问题，揭示了基态的准二维价带。我们的({rm{QSG}}hat{rm{W}})计算很好地再现了这些结果，并进一步确定了 X 点的某些带是主要具有 Br 和 S 特性的交换分裂态对。通过追踪带位置与温度的函数关系，我们发现分裂在 TN 以上消失了。能量分裂被解释为单个层中的有效交换分裂，其中 Cr 矩全部对齐，即所谓的 A 型反铁磁排列。我们的研究结果为解释 CrSBr 其他许多有趣的物理和光学特性奠定了坚实的基础。
{"title":"Giant exchange splitting in the electronic structure of A-type 2D antiferromagnet CrSBr","authors":"Matthew D. Watson, Swagata Acharya, James E. Nunn, Laxman Nagireddy, Dimitar Pashov, Malte Rösner, Mark van Schilfgaarde, Neil R. Wilson, Cephise Cacho","doi":"10.1038/s41699-024-00492-7","DOIUrl":"10.1038/s41699-024-00492-7","url":null,"abstract":"We present the evolution of the electronic structure of CrSBr from its antiferromagnetic ground state to the paramagnetic phase above TN = 132 K, in both experiment and theory. Low-temperature angle-resolved photoemission spectroscopy (ARPES) results are obtained using a novel method to overcome sample charging issues, revealing quasi-2D valence bands in the ground state. The results are very well reproduced by our $${rm{QSG}}hat{{rm{W}}}$$ calculations, which further identify certain bands at the X points to be exchange-split pairs of states with mainly Br and S character. By tracing band positions as a function of temperature, we show the splitting disappears above TN. The energy splitting is interpreted as an effective exchange splitting in individual layers in which the Cr moments all align, within the so-called A-type antiferromagnetic arrangement. Our results lay firm foundations for the interpretation of the many other intriguing physical and optical properties of CrSBr.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.1,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00492-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141940408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-11DOI: 10.1038/s41699-024-00491-8
Amira Bencherif, Monique Tie, Richard Martel, Delphine Bouilly
The transfer of two-dimensional materials from their growth substrate onto application wafers is a critical bottleneck in scaling-up devices based on such nanomaterials. Here, we present an innovative approach to achieve the automated and simultaneous transfer of arrays of graphene ribbons, with precise control over their orientation and alignment onto patterned wafers. The transfer is performed in a simple, yet efficient apparatus consisting of an array of glass columns, strategically shaped to control ribbon orientation and arranged to match the destination wafer, coupled to a dual inflow/outflow pumping system. This apparatus enables the transfer of a custom array of parallel graphene ribbons in a fraction of the time required with traditional methods. The quality of the transferred graphene was evaluated using optical imaging, scanning electron microscopy, hyperspectral Raman imaging, and electrical transport: all consistently indicating that the transferred graphene exhibits excellent quality, comparable to a manual transfer by an expert user. The proposed apparatus offers several competitive advantages, including ease of use, high transfer throughput, and reduced nanomaterial consumption. Moreover, it can be used repeatedly on the same wafer to assemble arrays of overlayed materials with controlled relative orientations. This approach thus opens promising opportunities for the large-scale fabrication of various heterostructures and devices based on vertical assemblies of 2D nanomaterials.
{"title":"Automated and parallel transfer of arrays of oriented graphene ribbons","authors":"Amira Bencherif, Monique Tie, Richard Martel, Delphine Bouilly","doi":"10.1038/s41699-024-00491-8","DOIUrl":"10.1038/s41699-024-00491-8","url":null,"abstract":"The transfer of two-dimensional materials from their growth substrate onto application wafers is a critical bottleneck in scaling-up devices based on such nanomaterials. Here, we present an innovative approach to achieve the automated and simultaneous transfer of arrays of graphene ribbons, with precise control over their orientation and alignment onto patterned wafers. The transfer is performed in a simple, yet efficient apparatus consisting of an array of glass columns, strategically shaped to control ribbon orientation and arranged to match the destination wafer, coupled to a dual inflow/outflow pumping system. This apparatus enables the transfer of a custom array of parallel graphene ribbons in a fraction of the time required with traditional methods. The quality of the transferred graphene was evaluated using optical imaging, scanning electron microscopy, hyperspectral Raman imaging, and electrical transport: all consistently indicating that the transferred graphene exhibits excellent quality, comparable to a manual transfer by an expert user. The proposed apparatus offers several competitive advantages, including ease of use, high transfer throughput, and reduced nanomaterial consumption. Moreover, it can be used repeatedly on the same wafer to assemble arrays of overlayed materials with controlled relative orientations. This approach thus opens promising opportunities for the large-scale fabrication of various heterostructures and devices based on vertical assemblies of 2D nanomaterials.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.1,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00491-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141940616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1038/s41699-024-00480-x
V. Tkáč, S. Vorobiov, P. Baloh, M. Vondráček, G. Springholz, K. Carva, P. Szabó, Ph. Hofmann, J. Honolka
FeTe monolayer islands situated on a topological insulator Bi2Te3 (0001) surface were recently reported to exhibit the opening of an energy gap below temperatures T ~ 6 K, which could be due to a superconducting phase transition. In this work, we present a magnetic field dependent transport study proving that this gap is indeed of superconducting origin. Upon cooling, several drops in resistance are observed in the temperature range between 6 K and 2 K, indicating multiple transitions. Using the Ginzburg-Landau theory, we show that the critical magnetic field of the dominant high-temperature transition at ~ 6 K is governed by orbital Cooper pair breaking in larger FeTe islands, large enough to exceed the superconductive coherence length $$xi$$ . At smaller island sizes, transitions at lower temperatures < 6 K become more prominent, showing significantly increased critical fields dominated by paramagnetic pair breaking. The multiphase superconducting behaviour is in line with an observed wide distribution of FeTe islands width 5–100 nm and seems to reflect disorder effects at the interface to Bi2Te3. The proof of local superconductivity makes the FeTe interface to the topological insulator Bi2Te3 substrate a potential host of topological superconductivity.
最近有报道称，位于拓扑绝缘体 Bi2Te3 (0001) 表面的铁碲单层岛在温度 T ~ 6 K 以下出现能隙，这可能是超导相变所致。在这项工作中，我们提出了一项磁场相关传输研究，证明这一间隙确实源于超导。冷却时，在 6 K 和 2 K 之间的温度范围内观察到电阻下降，这表明存在多重转变。利用金兹堡-朗道理论，我们证明了在 ~ 6 K 时主要高温转变的临界磁场受较大 FeTe 岛屿中轨道库珀对断裂的支配，大到足以超过超导相干长度 $$xi$$ 。在较小的铁碲岛中，较低温度 < 6 K 下的转变变得更加突出，显示出顺磁对断裂主导的临界磁场显著增加。多相超导行为与观察到的宽度为 5-100 nm 的 FeTe 岛的广泛分布一致，似乎反映了与 Bi2Te3 接口处的无序效应。局部超导电性的证明使拓扑绝缘体 Bi2Te3 衬底的 FeTe 界面成为拓扑超导电性的潜在宿主。
{"title":"Multiphase superconductivity at the interface between ultrathin FeTe islands and Bi2Te3","authors":"V. Tkáč, S. Vorobiov, P. Baloh, M. Vondráček, G. Springholz, K. Carva, P. Szabó, Ph. Hofmann, J. Honolka","doi":"10.1038/s41699-024-00480-x","DOIUrl":"10.1038/s41699-024-00480-x","url":null,"abstract":"FeTe monolayer islands situated on a topological insulator Bi2Te3 (0001) surface were recently reported to exhibit the opening of an energy gap below temperatures T ~ 6 K, which could be due to a superconducting phase transition. In this work, we present a magnetic field dependent transport study proving that this gap is indeed of superconducting origin. Upon cooling, several drops in resistance are observed in the temperature range between 6 K and 2 K, indicating multiple transitions. Using the Ginzburg-Landau theory, we show that the critical magnetic field of the dominant high-temperature transition at ~ 6 K is governed by orbital Cooper pair breaking in larger FeTe islands, large enough to exceed the superconductive coherence length $$xi$$ . At smaller island sizes, transitions at lower temperatures < 6 K become more prominent, showing significantly increased critical fields dominated by paramagnetic pair breaking. The multiphase superconducting behaviour is in line with an observed wide distribution of FeTe islands width 5–100 nm and seems to reflect disorder effects at the interface to Bi2Te3. The proof of local superconductivity makes the FeTe interface to the topological insulator Bi2Te3 substrate a potential host of topological superconductivity.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00480-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141928589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-02DOI: 10.1038/s41699-024-00490-9
Fengyi Zhou, Monirul Shaikh, Weiwei Sun, Feng Chen, Xin Chen, Shu Li, Henry Tong, Biplab Sanyal, Duo Wang
In the realm of multiferroicity in 2D magnets, whether magnetic and polar skyrmions can coexist within a single topological entity has emerged as an important question. Here, we study Janus 2D magnets CrInX3 (X=Se, Te) for a comprehensive investigation of the magnetic ground state, magnetic excited state, and corresponding ferroelectric polarization by first-principles electronic structure calculations and Monte Carlo simulations. Specifically, we have thoroughly elucidated the magnetic exchange mechanisms, and have fully exemplified the magnetic field dependence of the magnon spectrum. More importantly, our study reveals a previously unrecognized, remarkably large spin-spiral-induced ferroelectric polarization (up to 194.9 μC/m2) in both compounds. We propose an approach to identify polar skyrmions within magnetic skyrmions, based on the observed direct correlation between spin texture and polarization density. Elucidating this correlation not only deepens our understanding of magnetic skyrmions but also paves the way for innovative research in the realm of multiferroic skyrmions.
{"title":"Emergence of polar skyrmions in 2D Janus CrInX3 (X=Se, Te) magnets","authors":"Fengyi Zhou, Monirul Shaikh, Weiwei Sun, Feng Chen, Xin Chen, Shu Li, Henry Tong, Biplab Sanyal, Duo Wang","doi":"10.1038/s41699-024-00490-9","DOIUrl":"10.1038/s41699-024-00490-9","url":null,"abstract":"In the realm of multiferroicity in 2D magnets, whether magnetic and polar skyrmions can coexist within a single topological entity has emerged as an important question. Here, we study Janus 2D magnets CrInX3 (X=Se, Te) for a comprehensive investigation of the magnetic ground state, magnetic excited state, and corresponding ferroelectric polarization by first-principles electronic structure calculations and Monte Carlo simulations. Specifically, we have thoroughly elucidated the magnetic exchange mechanisms, and have fully exemplified the magnetic field dependence of the magnon spectrum. More importantly, our study reveals a previously unrecognized, remarkably large spin-spiral-induced ferroelectric polarization (up to 194.9 μC/m2) in both compounds. We propose an approach to identify polar skyrmions within magnetic skyrmions, based on the observed direct correlation between spin texture and polarization density. Elucidating this correlation not only deepens our understanding of magnetic skyrmions but also paves the way for innovative research in the realm of multiferroic skyrmions.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-12"},"PeriodicalIF":9.1,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00490-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1038/s41699-024-00484-7
Amir Kleiner, Daniel Hernangómez-Pérez, Sivan Refaely-Abramson
Optical properties of heterostructures composed of layered 2D materials, such as transition metal dichalcogenides (TMDs) and graphene, are broadly explored. Of particular interest are light-induced energy transfer mechanisms in these materials and their structural roots. Here, we use state-of-the-art first-principles calculations to study the excitonic composition and the absorption properties of WS2–graphene heterostructures as a function of interlayer alignment and the local strain resulting from it. We find that Brillouin zone mismatch and the associated energy level alignment between the graphene Dirac cone and the TMD bands dictate an interplay between interlayer and intralayer excitons, mixing together in the many-body representation upon the strain-induced symmetry breaking in the interacting layers. Examining the representative cases of the 0° and 30° interlayer twist angles, we find that this exciton mixing strongly varies as a function of the relative alignment. We quantify the effect of these structural modifications on exciton charge separation between the layers and the associated graphene-induced homogeneous broadening of the absorption resonances. Our findings provide guidelines for controllable optical excitations upon interface design and shed light on the importance of many-body effects in the understanding of optical phenomena in complex heterostructures.
{"title":"Designable exciton mixing through layer alignment in WS2-graphene heterostructures","authors":"Amir Kleiner, Daniel Hernangómez-Pérez, Sivan Refaely-Abramson","doi":"10.1038/s41699-024-00484-7","DOIUrl":"10.1038/s41699-024-00484-7","url":null,"abstract":"Optical properties of heterostructures composed of layered 2D materials, such as transition metal dichalcogenides (TMDs) and graphene, are broadly explored. Of particular interest are light-induced energy transfer mechanisms in these materials and their structural roots. Here, we use state-of-the-art first-principles calculations to study the excitonic composition and the absorption properties of WS2–graphene heterostructures as a function of interlayer alignment and the local strain resulting from it. We find that Brillouin zone mismatch and the associated energy level alignment between the graphene Dirac cone and the TMD bands dictate an interplay between interlayer and intralayer excitons, mixing together in the many-body representation upon the strain-induced symmetry breaking in the interacting layers. Examining the representative cases of the 0° and 30° interlayer twist angles, we find that this exciton mixing strongly varies as a function of the relative alignment. We quantify the effect of these structural modifications on exciton charge separation between the layers and the associated graphene-induced homogeneous broadening of the absorption resonances. Our findings provide guidelines for controllable optical excitations upon interface design and shed light on the importance of many-body effects in the understanding of optical phenomena in complex heterostructures.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-7"},"PeriodicalIF":9.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00484-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1038/s41699-024-00483-8
Chirag Chandrakant Palekar, Paulo E. Faria Junior, Barbara Rosa, Frederico B. Sousa, Leandro M. Malard, Jaroslav Fabian, Stephan Reitzenstein
Van der Waals heterostructures based on transition metal dichalcogenides exhibit physical properties that depend on their monolayer constituents’ twisting angle and stacking order. Particularly in type-II heterostructures, low-energy photoluminescence is dominated by interlayer excitons, resulting in low emission yields, which drastically hampers their optoelectronic applicability. This study reports on the photoluminescence quantum yield of heterostructures consisting of WSe2/WSe2/MoSe2 twisted layers. Our findings show that the additional WSe2 monolayer in the trilayer system enhances the low-energy photoluminescence by more than an order of magnitude depending on the WSe2/WSe2 twist-angle in comparison to their WSe2/MoSe2 heterobilayer counterpart. Furthermore, combining density functional theory calculations and extracted degree of circular polarization, we identify excitonic signatures arising from hybridized states that originate from the additional WSe2 layer. In addition to providing an additional understanding of hybridization effects in 2D semiconducting heterostructures, our findings provide a viable method to enhance emission in van der Waals heterostructures, relevant for studying the fundamental properties of excitons and enabling optoelectronic applications with high luminescence yield.
{"title":"Amplification of interlayer exciton emission in twisted WSe2/WSe2/MoSe2 heterotrilayers","authors":"Chirag Chandrakant Palekar, Paulo E. Faria Junior, Barbara Rosa, Frederico B. Sousa, Leandro M. Malard, Jaroslav Fabian, Stephan Reitzenstein","doi":"10.1038/s41699-024-00483-8","DOIUrl":"10.1038/s41699-024-00483-8","url":null,"abstract":"Van der Waals heterostructures based on transition metal dichalcogenides exhibit physical properties that depend on their monolayer constituents’ twisting angle and stacking order. Particularly in type-II heterostructures, low-energy photoluminescence is dominated by interlayer excitons, resulting in low emission yields, which drastically hampers their optoelectronic applicability. This study reports on the photoluminescence quantum yield of heterostructures consisting of WSe2/WSe2/MoSe2 twisted layers. Our findings show that the additional WSe2 monolayer in the trilayer system enhances the low-energy photoluminescence by more than an order of magnitude depending on the WSe2/WSe2 twist-angle in comparison to their WSe2/MoSe2 heterobilayer counterpart. Furthermore, combining density functional theory calculations and extracted degree of circular polarization, we identify excitonic signatures arising from hybridized states that originate from the additional WSe2 layer. In addition to providing an additional understanding of hybridization effects in 2D semiconducting heterostructures, our findings provide a viable method to enhance emission in van der Waals heterostructures, relevant for studying the fundamental properties of excitons and enabling optoelectronic applications with high luminescence yield.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.1,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00483-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141775084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.1038/s41699-024-00487-4
Gyula Halasi, Csaba Vass, Ka Man Yu, Gábor Vári, Arnold P. Farkas, Krisztián Palotás, András Berkó, János Kiss, Zoltán Kónya, Martin Aeschlimann, Benjamin Stadtmüller, Péter Dombi, László Óvári
Surface templating by electrostatic surface potentials is the least invasive way to design large-scale artificial nanostructures. However, generating sufficiently large potential gradients remains challenging. Here, we lay the groundwork for significantly enhancing local electrostatic fields by chemical modification of the surface. We consider the hexagonal boron nitride (h-BN) nanomesh on Rh(111), which already exhibits small surface potential gradients between its pore and wire regions. Using photoemission spectroscopy, we show that adding Au atoms to the Rh(111) surface layer leads to a local migration of Au atoms below the wire regions of the nanomesh. This significantly increases the local work function difference between the pore and wire regions that can be quantified experimentally by the changes in the h-BN valence band structure. Using density functional theory, we identify an electron transfer from Rh to Au as the microscopic origin for the local enhancement of potential gradients within the h-BN nanomesh.
{"title":"Enhancing the dipole ring of hexagonal boron nitride nanomesh by surface alloying","authors":"Gyula Halasi, Csaba Vass, Ka Man Yu, Gábor Vári, Arnold P. Farkas, Krisztián Palotás, András Berkó, János Kiss, Zoltán Kónya, Martin Aeschlimann, Benjamin Stadtmüller, Péter Dombi, László Óvári","doi":"10.1038/s41699-024-00487-4","DOIUrl":"10.1038/s41699-024-00487-4","url":null,"abstract":"Surface templating by electrostatic surface potentials is the least invasive way to design large-scale artificial nanostructures. However, generating sufficiently large potential gradients remains challenging. Here, we lay the groundwork for significantly enhancing local electrostatic fields by chemical modification of the surface. We consider the hexagonal boron nitride (h-BN) nanomesh on Rh(111), which already exhibits small surface potential gradients between its pore and wire regions. Using photoemission spectroscopy, we show that adding Au atoms to the Rh(111) surface layer leads to a local migration of Au atoms below the wire regions of the nanomesh. This significantly increases the local work function difference between the pore and wire regions that can be quantified experimentally by the changes in the h-BN valence band structure. Using density functional theory, we identify an electron transfer from Rh to Au as the microscopic origin for the local enhancement of potential gradients within the h-BN nanomesh.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-10"},"PeriodicalIF":9.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00487-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141775086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1038/s41699-024-00486-5
D. Manikandan, S. Karishma, Mukesh Kumar, Pramoda K. Nayak
Salinity gradient energy (SGE), known as blue energy is harvested from mixing seawater with river water in a controlled way using ion exchange membranes (IEMs). Using 2D materials as IEMs improves the output power density from a few Wm−2 to a few thousands of Wm−2 over conventional membranes. In this review, we survey the efforts taken to employ the different 2D materials as nanoporous or lamellar membranes for SGE and provide a comprehensive analysis of the fundamental principles behind the SGE. Overall, this review is anticipated to explain how the 2D materials can make SGE a viable source of energy.
{"title":"Salinity gradient induced blue energy generation using two-dimensional membranes","authors":"D. Manikandan, S. Karishma, Mukesh Kumar, Pramoda K. Nayak","doi":"10.1038/s41699-024-00486-5","DOIUrl":"10.1038/s41699-024-00486-5","url":null,"abstract":"Salinity gradient energy (SGE), known as blue energy is harvested from mixing seawater with river water in a controlled way using ion exchange membranes (IEMs). Using 2D materials as IEMs improves the output power density from a few Wm−2 to a few thousands of Wm−2 over conventional membranes. In this review, we survey the efforts taken to employ the different 2D materials as nanoporous or lamellar membranes for SGE and provide a comprehensive analysis of the fundamental principles behind the SGE. Overall, this review is anticipated to explain how the 2D materials can make SGE a viable source of energy.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-19"},"PeriodicalIF":9.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00486-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-18DOI: 10.1038/s41699-024-00481-w
Srinivasa Reddy Tamalampudi, Ghada Dushaq, Solomon M. Serunjogi, Nitul S. Rajput, Mahmoud S. Rasras
In integrated photonic circuits, microring resonators are essential building blocks but are susceptible to phase errors due to fabrication imperfections and optical power fluctuations. Conventional active phase tuning methods are power-intensive and challenging to integrate into densely packed photonic chips. This study proposes a solution by integrating a thin 2D layer of In4/3P2Se6 (InPSe) onto silicon microring resonators (Si-MRR). This approach mitigates sensitivity to laser power and achieves non-volatile wavelength trimming. Under bias voltage, the device exhibits electro-optic behavior, offering a non-volatile phase trimming rate of −2.62 pm/V to −4.62 pm/V, corresponding to InPSe thicknesses of 45 nm to 120 nm. Low optical losses of 0.0091 to 0.0361 dB/μm were also measured, corresponding to thicknesses of 30 nm to 120 nm. The devices demonstrate stable in-situ resonance wavelength stabilization and bidirectional trimming, ensuring cyclic stability for non-volatile phase control. This advancement enhances the performance of silicon photonics across diverse applications, facilitating high-capacity, high-power operation in compact designs.
{"title":"Simultaneous optical power insensitivity and non-volatile wavelength trimming using 2D In4/3P2Se6 integration in silicon photonics","authors":"Srinivasa Reddy Tamalampudi, Ghada Dushaq, Solomon M. Serunjogi, Nitul S. Rajput, Mahmoud S. Rasras","doi":"10.1038/s41699-024-00481-w","DOIUrl":"10.1038/s41699-024-00481-w","url":null,"abstract":"In integrated photonic circuits, microring resonators are essential building blocks but are susceptible to phase errors due to fabrication imperfections and optical power fluctuations. Conventional active phase tuning methods are power-intensive and challenging to integrate into densely packed photonic chips. This study proposes a solution by integrating a thin 2D layer of In4/3P2Se6 (InPSe) onto silicon microring resonators (Si-MRR). This approach mitigates sensitivity to laser power and achieves non-volatile wavelength trimming. Under bias voltage, the device exhibits electro-optic behavior, offering a non-volatile phase trimming rate of −2.62 pm/V to −4.62 pm/V, corresponding to InPSe thicknesses of 45 nm to 120 nm. Low optical losses of 0.0091 to 0.0361 dB/μm were also measured, corresponding to thicknesses of 30 nm to 120 nm. The devices demonstrate stable in-situ resonance wavelength stabilization and bidirectional trimming, ensuring cyclic stability for non-volatile phase control. This advancement enhances the performance of silicon photonics across diverse applications, facilitating high-capacity, high-power operation in compact designs.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-11"},"PeriodicalIF":9.1,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00481-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141730372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-15DOI: 10.1038/s41699-024-00485-6
Ali Sarafraz, Hanqing Liu, Katarina Cvetanović, Marko Spasenović, Sten Vollebregt, Tomás Manzaneque Garcia, Peter G. Steeneken, Farbod Alijani, Gerard J. Verbiest
Suspended drums made of 2D materials hold potential for sensing applications. However, the industrialization of these applications is hindered by significant device-to-device variations presumably caused by non-uniform stress distributions induced by the fabrication process. Here, we introduce a methodology to determine the stress distribution from their mechanical resonance frequencies and corresponding mode shapes as measured by a laser Doppler vibrometer (LDV). To avoid limitations posed by the optical resolution of the LDV, we leverage a manufacturing process to create ultra-large graphene drums with diameters of up to 1000 μm. We solve the inverse problem of a Föppl–von Kármán plate model by an iterative procedure to obtain the stress distribution within the drums from the experimental data. Our results show that the generally used uniform pre-tension assumption overestimates the pre-stress value, exceeding the averaged stress obtained by more than 47%. Moreover, it is found that the reconstructed stress distributions are bi-axial, which likely originates from the transfer process. The introduced methodology allows one to estimate the tension distribution in drum resonators from their mechanical response and thereby paves the way for linking the used fabrication processes to the resulting device performance.
{"title":"Quantifying stress distribution in ultra-large graphene drums through mode shape imaging","authors":"Ali Sarafraz, Hanqing Liu, Katarina Cvetanović, Marko Spasenović, Sten Vollebregt, Tomás Manzaneque Garcia, Peter G. Steeneken, Farbod Alijani, Gerard J. Verbiest","doi":"10.1038/s41699-024-00485-6","DOIUrl":"10.1038/s41699-024-00485-6","url":null,"abstract":"Suspended drums made of 2D materials hold potential for sensing applications. However, the industrialization of these applications is hindered by significant device-to-device variations presumably caused by non-uniform stress distributions induced by the fabrication process. Here, we introduce a methodology to determine the stress distribution from their mechanical resonance frequencies and corresponding mode shapes as measured by a laser Doppler vibrometer (LDV). To avoid limitations posed by the optical resolution of the LDV, we leverage a manufacturing process to create ultra-large graphene drums with diameters of up to 1000 μm. We solve the inverse problem of a Föppl–von Kármán plate model by an iterative procedure to obtain the stress distribution within the drums from the experimental data. Our results show that the generally used uniform pre-tension assumption overestimates the pre-stress value, exceeding the averaged stress obtained by more than 47%. Moreover, it is found that the reconstructed stress distributions are bi-axial, which likely originates from the transfer process. The introduced methodology allows one to estimate the tension distribution in drum resonators from their mechanical response and thereby paves the way for linking the used fabrication processes to the resulting device performance.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.1,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00485-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141624597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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