arXiv: Materials Science最新文献

A pathway towards high throughput Quantum Monte Carlo simulations for alloys: A case study of two-dimensional (2D) GaSₓSe₁₋ₓ 通往合金高通量量子蒙特卡罗模拟的途径:二维(2D) GaS的案例研究ₓSe₁ₓ

arXiv: Materials Science Pub Date : 2021-07-13 DOI: 10.13016/M2UVJO-QHHM

D. Wines, Kayahan Saritas, C. Ataca

引用次数: 0

Data analytics accelerates the experimental discovery of new thermoelectric materials with extremely high figure of merit 数据分析加速了具有极高价值的新型热电材料的实验发现

arXiv: Materials Science Pub Date : 2021-04-16 DOI: 10.21203/rs.3.rs-926972/v1

S. Levchenko, Yaqiong Zhong, Xiaojuan Hu, Debalaya Sarker, Qingrui Xia, Liangliang Xu, Chao Yang, Zhongkang Han, J. Cui

{"title":"Data analytics accelerates the experimental discovery of new thermoelectric materials with extremely high figure of merit","authors":"S. Levchenko, Yaqiong Zhong, Xiaojuan Hu, Debalaya Sarker, Qingrui Xia, Liangliang Xu, Chao Yang, Zhongkang Han, J. Cui","doi":"10.21203/rs.3.rs-926972/v1","DOIUrl":"https://doi.org/10.21203/rs.3.rs-926972/v1","url":null,"abstract":"\u0000 Thermoelectric (TE) materials are among very few sustainable yet feasible energy solutions of present time. This huge promise of energy harvesting is contingent on identifying/designing materials having higher efficiency than presently available ones. However, due to the vastness of the chemical space of materials, only its small fraction was scanned experimentally and/or computationally so far. Employing a compressed-sensing based symbolic regression in an active-learning framework, we have not only identified a trend in materials’ compositions for superior TE performance, but have also predicted and experimentally synthesized several extremely high performing novel TE materials. Among these, we found polycrystalline p-type Cu0.45Ag0.55GaTe2 to possess an experimental figure of merit as high as ~2.8 at 827 K. This is a breakthrough in the field, because all previously known thermoelectric materials with a comparable figure of merit are either unstable or much more difficult to synthesize, rendering them unusable in large-scale applications. The presented methodology demonstrates the importance and tremendous potential of physically informed descriptors in material science, in particular for relatively small data sets typically available from experiments at well-controlled conditions.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86111548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Thermal laser evaporation of elements from across the periodic table 热激光蒸发元素周期表中的元素

arXiv: Materials Science Pub Date : 2021-03-23 DOI: 10.2351/7.0000348

Thomas J. Smart, J. Mannhart, W. Braun

引用次数: 6

Perpendicular magnetic anisotropy in ultra-thin Cu2Sb-type (Mn–Cr)AlGe films fabricated onto thermally oxidized silicon substrates 热氧化硅衬底上制备的超薄cu2sb型(Mn-Cr)AlGe薄膜的垂直磁各向异性

arXiv: Materials Science Pub Date : 2021-03-14 DOI: 10.1063/5.0049899

T. Kubota, K. Ito, R. Umetsu, K. Takanashi

{"title":"Perpendicular magnetic anisotropy in ultra-thin Cu2Sb-type (Mn–Cr)AlGe films fabricated onto thermally oxidized silicon substrates","authors":"T. Kubota, K. Ito, R. Umetsu, K. Takanashi","doi":"10.1063/5.0049899","DOIUrl":"https://doi.org/10.1063/5.0049899","url":null,"abstract":"Perpendicularly magnetized films showing small saturation magnetization, $M_mathrm{s}$, are essential for spin-transfer-torque writing type magnetoresistive random access memories, STT-MRAMs. An intermetallic compound, {(Mn-Cr)AlGe} of the Cu$_2$Sb-type crystal structure was investigated, in this study, as a material showing the low $M_mathrm{s}$ ($sim 300$ kA/m) and high-perpendicular magnetic anisotropy, $K_mathrm{u}$. The layer thickness dependence of $K_mathrm{u}$ and effects of Mg-insertion layers at top and bottom (Mn-Cr)AlGe$|$MgO interfaces were studied in film samples fabricated onto thermally oxidized silicon substrates to realize high-$K_mathrm{u}$ in the thickness range of a few nanometer. Optimum Mg-insertion thicknesses were 1.4 and 3.0 nm for the bottom and the top interfaces, respectively, which were relatively thick compared to results in similar insertion effect investigations on magnetic tunnel junctions reported in previous studies. The cross-sectional transmission electron microscope images revealed that the Mg-insertion layers acted as barriers to interdiffusion of Al-atoms as well as oxidization from the MgO layers. The values of $K_mathrm{u}$ were about $7 times 10^5$ and $2 times 10^5$ J/m$^3$ at room temperature for 5 and 3 nm-thick (Mn-Cr)AlGe films, respectively, with the optimum Mg-insertion thicknesses. The $K_mathrm{u}$ at a few nanometer thicknesses is comparable or higher than those reported in perpendicularly magnetized CoFeB films which are conventionally used in MRAMs, while the $M_mathrm{s}$ value is one third or less smaller than those of the CoFeB films. The developed (Mn-Cr)AlGe films are promising from the viewpoint of not only the magnetic properties, but also the compatibility to the silicon process in the film fabrication.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80009358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

The Mesoscale Crystallinity of Nacreous Pearls 珍珠的中尺度结晶度

arXiv: Materials Science Pub Date : 2021-03-11 DOI: 10.21203/RS.3.RS-278534/V1

J. Gim, Alden Koch, L. Otter, B. Savitzky, S. Erland, L. Estroff, Dorrit Jacob, R. Hovden

{"title":"The Mesoscale Crystallinity of Nacreous Pearls","authors":"J. Gim, Alden Koch, L. Otter, B. Savitzky, S. Erland, L. Estroff, Dorrit Jacob, R. Hovden","doi":"10.21203/RS.3.RS-278534/V1","DOIUrl":"https://doi.org/10.21203/RS.3.RS-278534/V1","url":null,"abstract":"\u0000 A pearl’s distinguished beauty and toughness is attributable to the periodic stacking of aragonite tablets known as nacre. Nacre is a naturally occurring mesocrystal that remarkably arises in the absence of translational symmetry. Gleaning the inspiring biomineral design of a pearl requires quantifying its structural coherence and understanding the stochastic processes that govern formation. By characterizing the entire structure of pearls (~3 mm) in cross-section at high resolution, we show nacre is a medium-range mesocrystal formed through nanoparticle assembly processes. Self-correcting growth mechanisms actively remedy disorder and topological defects of the tablets and act as a countervailing force to paracrystallinity (i.e. long-range disorder). Nacre has a correlation length of roughly 16 tablets (~5.5 µm) despite persistent fluctuations and topological defects. For longer distances (> 25 tablets, ~8.5 µm), the frequency spectrum of nacre tablets follows f-1.5 behavior suggesting growth is coupled to external stochastic processes—a universality found across disparate natural phenomena which now includes pearls.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79239399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Polycrystal plasticity and grain boundary evolution: A unified dislocation-based diffuse-interface approach 多晶塑性和晶界演化:基于位错的扩散界面方法

arXiv: Materials Science Pub Date : 2021-02-01 DOI: 10.13140/RG.2.2.28625.45923

Junyang He, N. Admal

{"title":"Polycrystal plasticity and grain boundary evolution: A unified dislocation-based diffuse-interface approach","authors":"Junyang He, N. Admal","doi":"10.13140/RG.2.2.28625.45923","DOIUrl":"https://doi.org/10.13140/RG.2.2.28625.45923","url":null,"abstract":"Grain structure plays a key role in the mechanical properties of alloy materials. Engineering the grain structure requires a comprehensive understanding of the evolution of grain boundaries (GBs) when a material is subjected to various manufacturing processes. To this end, we present a computationally efficient framework to describe the co-evolution of bulk plasticity and GBs. We represent GBs as diffused geometrically necessary dislocations, whose evolution describes GB plasticity. Under this representation, the evolution of GBs and bulk plasticity can be described in unison using the evolution equation for the plastic deformation gradient, an equation central to classical crystal plasticity theories. In addition, we outline a method to introduce a synthetic potential to drive migration of a flat GB within our diffuse-interface framework. We validate the framework by simulating the evolution of a triple junction, and demonstrate its computational efficiency. We further leverage this framework to study the migration of a flat GB driven by a potential difference, subject to different sets of available slip systems and mechanical boundary conditions.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80603569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A crystal symmetry-invariant Kobayashi--Warren--Carter grain boundary model and its implementation using a thresholding algorithm 晶体对称不变的Kobayashi- Warren- Carter晶界模型及其阈值算法实现

arXiv: Materials Science Pub Date : 2021-02-01 DOI: 10.13140/RG.2.2.27993.54881

Jaekwang Kim, M. Jacobs, S. Osher, N. Admal

{"title":"A crystal symmetry-invariant Kobayashi--Warren--Carter grain boundary model and its implementation using a thresholding algorithm","authors":"Jaekwang Kim, M. Jacobs, S. Osher, N. Admal","doi":"10.13140/RG.2.2.27993.54881","DOIUrl":"https://doi.org/10.13140/RG.2.2.27993.54881","url":null,"abstract":"One of the most important aims of grain boundary modeling is to predict the evolution of a large collection of grains in phenomena such as abnormal grain growth, coupled grain boundary motion, and recrystallization that occur under extreme thermomechanical loads. A unified framework to study the coevolution of grain boundaries with bulk plasticity has recently been developed by Admal et al. (2018), which is based on modeling grain boundaries as continuum dislocations governed by an energy based on the Kobayashi--Warren--Carter (KWC) model (Kobayashi et al., 1998, 2000). While the resulting unified model demonstrates coupled grain boundary motion and polygonization (seen in recrystallization), it is restricted to grain boundary energies of the Read--Shockley type, which applies only to small misorientation angles. In addition, the implementation of the unified model using finite elements inherits the computational challenges of the KWC model that originate from the singular diffusive nature of its governing equations. The main goal of this study is to generalize the KWC functional to grain boundary energies beyond the Read--Shockley-type that respect the bicrystallography of grain boundaries. The computational challenges of the KWC model are addressed by developing a thresholding method that relies on a primal dual algorithm and the fast marching method, resulting in an O(NlogN) algorithm, where N is the number of grid points. We validate the model by demonstrating the Herring angle relation, followed by a study of the grain microstructure evolution in a two-dimensional face-centered cubic copper polycrystal with crystal symmetry-invariant grain boundary energy data obtained from the lattice matching method of Runnels et al. (2016a,b).","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84450833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Sintering BFO targets for sputtering 烧结BFO溅射靶材

arXiv: Materials Science Pub Date : 2021-02-01 DOI: 10.34049/bcc.52.C.0047

G. Orr, A. Goryachev, G. Golan

引用次数: 1

Comparison of measured and simulated spin-wave mode spectra of magnetic nanostructures. 磁性纳米结构自旋波模式光谱的测量与模拟比较

arXiv: Materials Science Pub Date : 2021-01-01 DOI: 10.1063/5.0039188

H T Nembach, R D McMichael, M L Schneider, J M Shaw, T J Silva

{"title":"Comparison of measured and simulated spin-wave mode spectra of magnetic nanostructures.","authors":"H T Nembach, R D McMichael, M L Schneider, J M Shaw, T J Silva","doi":"10.1063/5.0039188","DOIUrl":"10.1063/5.0039188","url":null,"abstract":"Motivated by the importance of magnetization dynamics in nanomagnets for the development and optimization of magnetic devices and sensors, we measured and modeled spin wave spectra in patterned elliptical nanomagnets. Ferromagnetic resonance spectra for multiple nanomagnets of Ni80Fe20, fabricated by electron-beam lithography to have nominal short-axes of 200 nm or 100 nm, were measured by use of heterodyne magneto-optical microwave microscopy. Scanning electron microscope images taken of the same nanomagnets were used to define element shapes for micromagnetic simulations. The measured spectra show significant differences between nominally identical nanomagnets, which could be only partially attributed to uncontrolled shape variations in the patterning process, as evidenced by the limited agreement between the measured and simulated spectra. Agreement between measurements and simulations was improved by including a zone of reduced magnetization and exchange at the edges of the nanomagnets in the simulations. Our results show that the reduction of shape variations between individual magnetic random-access memory elements can potentially improve their performance. However, unambiguous determination of materials parameters in nanomagnets based on analysis and modeling of spin wave spectra remains problematic.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11653420/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79395006","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}

引用次数: 0

Effect of different device parameters on tin-based perovskite solar cell coupled with In2S3 electron transport layer and CuSCN and Spiro-OMeTAD alternative hole transport layers for high-efficiency performance 不同器件参数对锡基钙钛矿太阳能电池耦合In2S3电子传输层和CuSCN和Spiro-OMeTAD替代空穴传输层的高效性能的影响

arXiv: Materials Science Pub Date : 2020-12-16 DOI: 10.1080/15567036.2020.1820628

Intekhab Alam, Md Ali Ashraf

{"title":"Effect of different device parameters on tin-based perovskite solar cell coupled with In2S3 electron transport layer and CuSCN and Spiro-OMeTAD alternative hole transport layers for high-efficiency performance","authors":"Intekhab Alam, Md Ali Ashraf","doi":"10.1080/15567036.2020.1820628","DOIUrl":"https://doi.org/10.1080/15567036.2020.1820628","url":null,"abstract":"SCAPS 1-D was used for the simulation of lead-free environmentally benign methylammonium tin-iodide (CH3NH3SnI3) based solar cell. Indium sulphide (In2S3) was utilized as the electron transport layer (ETL) for its high carrier mobility and optimized band structure, unlike traditional titanium oxide (TiO2) ETL. Traditional expensive spiro-OMeTAD (C81H68N4O8) and cheaper cuprous thiocyanate (CuSCN) were utilized alternatively as hole transport layer (HTL) to observe the effect of different HTL on cell performance. We investigated the trend in electrical measurements by altering parameters such as thickness, defect density, valence band (VB) effective density of state and bandgap of the absorber layer, interfacial trap densities and defect density of ETL. At optimum condition, the device revealed the highest efficiency of 18.45% for CuSCN (HTL) and 19.32% for spiro-OMeTAD (HTL) configuration. The effect of working temperature, the wavelength of light and band-to-band radiative recombination rate was also observed for both configurations. All these simulation results will help to fabricate eco-friendly high-efficiency perovskite solar cell by replacing the commonly used toxic lead-based perovskite.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85013049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 40