Communications in Physics最新文献_第8页

Unfolding Band and Absorption Energy Shift of (text{Si-Ge}) Nano Crystals from First-principles Calculations 从第一性原理计算(text{Si-Ge})纳米晶体的展开能带和吸收能移

Communications in Physics Pub Date : 2021-04-16 DOI: 10.15625/0868-3166/14942

V. Tran, Duong Tran Thi Thuy, Cong Le Thanh, Ha Ngo Ngoc, Nhung Nguyen Thi Thuy, Viet Nguyen Huy

{"title":"Unfolding Band and Absorption Energy Shift of (text{Si-Ge}) Nano Crystals from First-principles Calculations","authors":"V. Tran, Duong Tran Thi Thuy, Cong Le Thanh, Ha Ngo Ngoc, Nhung Nguyen Thi Thuy, Viet Nguyen Huy","doi":"10.15625/0868-3166/14942","DOIUrl":"https://doi.org/10.15625/0868-3166/14942","url":null,"abstract":"Physical properties of the Si1−xGex alloys (x being the composition of Ge) can be understood and predicted from their electronic band structures. In this paper, electronic band structures of the Si1−xGex alloys are calculated using the first-principles density functional theory. The supper cell approach employed in our calculations leads to folding of electronic bands into the smaller Brillouin zone of the supercell, especially at the Γ point. This often leads to the misinterpretation that the materials have direct band gap. The problem can be resolved by an unfolding band technique which allows us to recover the primitive cell picture of band structure of Si1−xGex. As a result, unfolded electronic bands correctly show an indirect band gap with the valence band maximum (VBM) at the Γ point and the conduction band minimum (CBM) shifted away from Γ. CBM is gradually shifted from a point along ΓX symmetry line (associated with Si) to the L point (associated with Ge) with the increased Ge composition x and the switching occurs at x in the range of 0.6∼0.8 which is in accordance with the calculation using kp method. Moreover, the additional electron pockets appear and develop at Γ and L. This provides more comprehensive understanding for our recent experimental observations on the shift of the absorption energy assigned to E1 direct transitions within L and Γ points in the Brillouin zone of Si1−xGex alloy nanocrystals.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89235796","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

Magnetic Domain Walls Moving in Curved Permalloy Nanowires under Continuous and Pulsed Fields 连续和脉冲磁场下弯曲坡莫合金纳米线中的磁畴壁运动

Communications in Physics Pub Date : 2021-03-15 DOI: 10.15625/0868-3166/15768

Quang Duc Hoang, Huu Xuan Cao, Thuong H. Nguyen, Ai Vinh Dao

{"title":"Magnetic Domain Walls Moving in Curved Permalloy Nanowires under Continuous and Pulsed Fields","authors":"Quang Duc Hoang, Huu Xuan Cao, Thuong H. Nguyen, Ai Vinh Dao","doi":"10.15625/0868-3166/15768","DOIUrl":"https://doi.org/10.15625/0868-3166/15768","url":null,"abstract":"Magnetic domain walls created and propagated in curved permalloy nanowires under continuous and pulsed fields in a Lorentz microscope. Using such nanowires aims to create a single or multiple magnetic domain walls in typical areas of those structures, an external magnetic field then applies along the long axis of these nanowires. Following that the created domain walls are propagated from one end to the other end of each wire by increasing the continuous/pulsed field strength. At each increased field value, a Fresnel image is recorded. The obtained results show that the characteristics of those created and propagated domain walls are dependent on various parameters, i.e. connecting structures, wall types and chiralities. Corners between the straight and linking sections of those curved nanowires also play a crucial role along with the local defects created in these wire-edges and surfaces where a point-defect is considered as a potential well that could pin/distort those created/propagated domain walls. By the aid of these observations, the dynamic properties of domain walls with the creating and propagating processes in those curved nanowires are exposed. These outcomes are vital to design novel domain wall trap structures supporting reproducible domain wall motions. That are of interest in providing a better understanding of multiple bits moving in the future 3D racetrack memory, logic gates, shift register and other spintronic/computing devices.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"91 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90703025","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

Anisotropic Magnetoresistance Effect of Nickel Nanowires 镍纳米线的各向异性磁阻效应

Communications in Physics Pub Date : 2021-01-27 DOI: 10.15625/0868-3166/15674

Do Chung Pham, V. T. Ngo, J. Wegrowe

引用次数: 0

Size effect of R-TiO(_{2}) (Micro- and Nano-) Particles on the Mechanical Property, Weathering Durability of Water-based Acrylic Coating R-TiO (_{2})(微纳)颗粒尺寸对水性丙烯酸涂料力学性能和耐候性的影响

Communications in Physics Pub Date : 2021-01-09 DOI: 10.15625/0868-3166/15443

T. Nguyen, T. M. Dang, T. Nguyen, T. Hoang

{"title":"Size effect of R-TiO(_{2}) (Micro- and Nano-) Particles on the Mechanical Property, Weathering Durability of Water-based Acrylic Coating","authors":"T. Nguyen, T. M. Dang, T. Nguyen, T. Hoang","doi":"10.15625/0868-3166/15443","DOIUrl":"https://doi.org/10.15625/0868-3166/15443","url":null,"abstract":"This work aims to clarify the difference between the influence of TiO2 particles at micrometer and nanometer sizes on the mechanical properties and weathering durability of waterbased acrylic coatings. To prepare coatings, micro-R-TiO2 and nano R-TiO2 particles with 2 wt.% content were dispersed in the emulsion acrylic polymer by ultrasonic vibration. The coatings without TiO2 particles, with 2 wt.% micro R-TiO2 and with 2 wt.% nano R-TiO2 were tested for abrasion resistance, weathering aging in UV/CON accelerated weathering chamber. Weathering aging was assessed by IR quantitative analysis, the weight loss of the coating. The obtained results showed that the micro R-TiO2 with the 2 wt.% content enhanced simultaneously the abrasion resistance and weathering durability of water-based acrylic coatings but not as effectively as nano R-TiO2. Incorporation of 2 wt.% micro-R-TiO2 increased slightly the abrasion resistance of coating from 78.4 to 98.9 lite/mil (26% increase) while with addition of nano-R-TiO2 at the same content, the abrasion resistance was significantly improved from 78.4 to 129.3 lite/mil (65% increase). After 48 aging cycles, the alkane CH groups and weight of the coatings without RTiO2 particles, containing 2 wt.% micro-R-TiO2, containing nano-R-TiO2 lost 34.2% and 17.4%; 23.8% and 13%; 13.7% and 13 %, respectively.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"65 1","pages":"219"},"PeriodicalIF":0.0,"publicationDate":"2021-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86412395","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

REMOVAL OF RHODAMINE B DYE BY PLASMA JET OXIDATION PROCESS 等离子体喷射氧化法去除罗丹明b染料

Communications in Physics Pub Date : 2020-12-30 DOI: 10.15625/0868-3166/15558

Thuan Dao Nguyen

引用次数: 2

MULTIBAND METAMATERIAL ABSORBER IN A RING STRUCTURE BASE ON HIGH-ORDER MAGNETIC RESONANCE 基于高阶磁共振的环形结构多波段超材料吸收体

Communications in Physics Pub Date : 2020-12-30 DOI: 10.15625/0868-3166/15520

Thi Hien Nguyen

{"title":"MULTIBAND METAMATERIAL ABSORBER IN A RING STRUCTURE BASE ON HIGH-ORDER MAGNETIC RESONANCE","authors":"Thi Hien Nguyen","doi":"10.15625/0868-3166/15520","DOIUrl":"https://doi.org/10.15625/0868-3166/15520","url":null,"abstract":"We proposed a multiband metamaterial absorber(MMA) based on high-order magnetic resonance using ring-shaped structures. This MMA is not only simple with highly symmetric geometry but also effectively absorptive with multi-band and down- scalability. It was found that the absorption occurred at some specific frequencies, which are three times and five times higher than that of common structures, originates from the magnetic resonances. In particular, the obtained results can be theoretically explained by using the LC circuit model. In addition, by scaling down the unit-cell size, the third- and fifth-order magnetic resonances are created at the THz frequencies. The presence of multiple absorption peaks opens the possibility for MMAs working from the GHz to the THz band.We proposed a multiband metamaterial absorber(MMA) based on high-order magnetic resonance using ring-shaped structures. This MMA is not only simple with highly symmetric geometry but also effectively absorptive with multi-band and down- scalability. It was found that the absorption occurred at some specific frequencies, which are three times and five times higher than that of common structures, originates from the magnetic resonances. In particular, the obtained results can be theoretically explained by using the LC circuit model. In addition, by scaling down the unit-cell size, the third- and fifth-order magnetic resonances are created at the THz frequencies. The presence of multiple absorption peaks opens the possibility for MMAs working from the GHz to the THz band.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73677839","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

Interaction Between Two Jackiw-Rebbi States in Interfaced Binary Waveguide Arrays with Cubic-quintic Nonlinearity 具有三次五次非线性的界面二元波导阵列中两个jacki - rebbi态的相互作用

Communications in Physics Pub Date : 2020-12-30 DOI: 10.15625/0868-3166/15178

X. T. Tran, Nhu Xuan Nguyen, The Quang Nguyen, Van Toan Nguyen, T. Nguyen

引用次数: 0

Synthesis of ZnSe Nanocrystals for Solid-state Lighting Applications 用于固态照明的ZnSe纳米晶体的合成

Communications in Physics Pub Date : 2020-12-30 DOI: 10.15625/0868-3166/15358

T. Chi, B. Hien, Hoang Nhu Thanh, Trinh Duc Thien, P. N. Hai

引用次数: 0

NUCLEAR MEAN-FIELD DESCRIPTION OF PROTON ELASTIC SCATTERING BY 12,13 C AT LOW ENERGIES 低能下质子弹性散射12,13c的核平均场描述

Communications in Physics Pub Date : 2020-12-30 DOI: 10.15625/0868-3166/15278

H. Phan