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In this paper, the structure of cubic CaTiO3 (001) surfaces with CaO and TiO2 terminations has been studied from density functional calculations. It has been found that the Ca atom has the largest relaxation for both kinds of terminations, and the rumpling of the CaO-terminated surface is much larger than that of TiO2-terminated surface. Also we have found that the metal atom relaxes much more prominently than the O atom does in each layer. The CaO-terminated surface is slightly more energetically favourahle than the TiO2-terminated surface from the analysis of the calculated surface energy. 相似文献
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Deposition of Cu seed layer film by supercritical fluid deposition for advanced interconnects 下载免费PDF全文
The deposition of a Cu seed layer film is investigated by supercritical fluid deposition(SCFD) using H2 as a reducing agent for Bis(2,2,6,6-tetramethyl-3,5-heptanedionato) copper in supercritical CO2(scCO2).The effects of deposition temperature,precursor,and H2 concentration are investigated to optimize Cu deposition.Continuous metallic Cu films are deposited on Ru substrates at 190℃ when a 0.002 mol/L Cu precursor is introduced with 0.75 mol/L H2.A Cu precursor concentration higher than 0.002 mol/L is found to have negative effects on the surface qualities of Cu films.For a H2 concentration above 0.56 mol/L,the root-mean-square(RMS) roughness of a Cu film decreases as the H2 concentration increases.Finally,a 20-nm thick Cu film with a smooth surface,which is required as a seed layer in advanced interconnects,is successfully deposited at a high H2 concentration(0.75 mol/L). 相似文献
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Ferroelectric Properties of Polycrystalline Ceramics with Dipolar Defect Simulated from the Potts--Ising Model 下载免费PDF全文
Physical properties of polycrystailine ferroelectrics including the contributions of the fixed dipolar defects and the average grain size in the Potts-Ising model are simulated by using the Monte Carlo method. Domain pattern, hysteresis loop and switching current of the polarization reversal process are obtained. Two processes are considered in our simulation. In the first one, the grain texture of ferroelectric ceramics are produced from the Ports model, and then the Ising model is implemented in the obtained polycrystailine texture to produce the domain pattern, hysteresis loop and switching current. It is concluded that the defect has the ability to decrease the remnant polarization P~ as well as the coercive field E~. The back switching is obviously observed after the electric field is off, and it shows some variation after introducing the fixed dipolar defect. Meanwhile, the spike of the switching current is found to lower with the increasing defect concentration and the decreasing average grain size. 相似文献
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Surface rumples and band gap reductions of cubic BaZrO3 (001) surface studied by means of first-principles calculations 下载免费PDF全文
Electronic properties of the (001) surface of cubic BaZrO3 with BaO and ZrO2 terminations have been studied using first-principles calculations. Surface structure, partial density of states, band structure and surface energy have been obtained. We find that the largest relaxation appears in the first layer of atoms, and the relaxation of the BaO-terminated surface is larger than that of the ZrO2-terminated surface. The surface rumpling of the BaO-terminated surface is also larger than that of the ZrO2-terminated surface. Results of surface energy calculations reveal that the BaZrO3 surface is likely to be more stable than the PbZrO3 surface. 相似文献
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Potts-Ising model for simulation of polarization switching in polycrystalline ferroelectrics 下载免费PDF全文
This paper proposes a scheme based on the Potts and Ising models for
simulating polarization switching of polycrystalline ferroelectrics
using the Monte Carlo method. The polycrystalline texture with
different average grain size is produced from the Potts model. Then
Ising model is implemented in the polycrystalline texture to produce
the domain pattern and hysteresis loop. The domain patterns and
hysteresis loops have been obtained for polycrystalline texture with
different average grain size. From the results of domain pattern
evolution process under an applied electric field using this scheme,
an extended domain, which covers more than one grain with
polarization aligned roughly in the same direction, has been
observed during the polarization reversal. This scheme can well
reproduce the basic properties of polycrystalline ferroelectrics and
is a valuable tool for exploring the physical properties of
polycrystalline ferroelectrics. 相似文献
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设计了一种以太阳能为驱动力,利用渗透压将水分从蒸发器端传输到冷凝器端的压差式吸附制冷机.水分先在蒸发器端被吸附板吸收,再通过渗透压自动运输到最后环节段,并被膨胀物质间歇式地挤压出吸水材料,进入冷凝器,从而保证水分不断从蒸发器抽出,产生制冷效果.通过改变太阳能制冷系统的四通换向阀的开启方向,实现吸附式制冷系统的连续制冷. 相似文献
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