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基于密度泛函理论的第一性原理方法,系统研究了三元金属间化合物SrAlSi在高压下的电子性质和晶格动力学性质.三元金属间化合物SrAlSi具有和MgB2类似的六角蜂巢状结构,Sr原子取代了Mg原子的位置,Al、Si原子无序地占据B原子的位子.通过对SrAlSi三元金属间化合物能带和三维费米面的计算,发现在压力的作用下SrAlSi费米面附近的能带发生电子拓扑变化,压力可以导致电子拓扑结构相变(ETTs).通过晶格动力学研究发现,在压力的作用下,SrAlSi的光学支沿着A-L-H方向逐渐软化,声学支逐渐变硬,说明金属间化合物SrAlSi在压力作用下结构不是很稳定,随着压力的继续增大,会有新的结构出现. 相似文献
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Structural,optical,and electrical properties of Cu-doped ZrO_2 films prepared by magnetron co-sputtering 下载免费PDF全文
Copper(Cu)-doped ZrO_2(CZO) films with different Cu content(0 at.%~ 8.07 at.%) are successfully deposited on Si(100) substrates by direct current(DC) and radio frequency(RF) magnetron co-sputtering. The influences of Cu content on structural, morphological, optical and electrical properties of CZO films are discussed in detail. The CZO films exhibit ZrO_2 monocline(ˉ111) preferred orientation, which indicates that Cu atoms are doped in ZrO_2 host lattice. The crystallite size estimated form x-ray diffraction(XRD) increases by Cu doping, which accords with the result observed from the scanning electron microscope(SEM). The electrical resistivity decreases from 2.63 ?.cm to 1.48 ?·cm with Cu doping content increasing, which indicates that the conductivity of CZO film is improved. However, the visible light transmittances decrease slightly by Cu doping and the optical band gap values decrease from 4.64 eV to 4.48 eV for CZO films. 相似文献
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利用基于密度泛函理论的第一性原理方法,研究了三元金属间化合物CaAlSi在高压下的电子性质和晶格振动性质。三元金属间化合物CaAlSi具有和MgB2类似的六角蜂巢状结构,Ca原子取代了Mg原子的位置,Al、Si原子无序地占据B原子的位子。通过对Ca三元金属间化合物能带和三维费米面的计算,发现在压力的作用下CaAlSi费米面附近的能带发生了电子拓扑变化,压强可以导致电子拓扑结构相变(ETTs)。通过晶格动力学的研究发现,在压力的作用下,CaAlSi的光学支沿着A-L-H方向逐渐软化,声学支逐渐变硬。说明此金属间化合物在压力的作用下,其结构不是很稳定,随着压力的继续增大,可能会有新的结构出现。 相似文献
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Electron field emission characteristics of nano-catkin carbon films deposited by electron cyclotron resonance microwave plasma chemical vapour deposition 下载免费PDF全文
This paper reported that the nano-catkin carbon films were prepared on Si substrates by means of electron cyclotron resonance microwave plasma chemical vapour deposition in a hydrogen and methane mixture. The surface morphology and the structure of the fabricated films were characterized by using scanning electron microscopes and Raman spectroscopy, respectively. The stable field emission properties with a low threshold field of 5V/μm corresponding to a current density of about 1μA/cm^2 and a current density of 3.2mA/cm^2 at an electric field of 10V/μm were obtained from the carbon film deposited at CH4 concentration of 8%. The mechanism that the threshold field decreased with the increase of the CH4 concentration and the high emission current appeared at the high CH4 concentration was explained by using the Fowler-Nordheim theory. 相似文献
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采用直流磁控共溅射技术, 以Ar与N2为源气体, 硅片为衬底成功地制备了Fe, Mn掺杂AlN薄膜. 利用X射线衍射和拉曼光谱研究了工作电流、靶基距离等工艺参数的改变对薄膜结构的影响. 利用扫描电子显微镜和能谱分析仪对薄膜的表面形貌和组成成分进行了分析. 利用振动样品磁强计在室温下对Fe, Mn掺杂AlN薄膜进行了磁性表征. Mn掺杂AlN薄膜表现出顺磁性的原因可能是由于Mn掺杂浓度较高, 在沉积过程部分Mn以团簇的形式存在, 反铁磁性的Mn团簇减弱了体系的铁磁交换作用. Fe掺杂AlN薄膜表现出室温铁磁性, 这可能是AlFeN三元化合物作用的结果. 随着Fe 掺杂AlN薄膜中Fe原子浓度从6.81%增加到16.17%, 其饱和磁化强度Ms由0.27 emu·cm-3逐渐下降到0.20 emu·cm-3, 而矫顽力Hc则由57 Oe增大到115 Oe (1 Oe=79.5775 A/m), 这一现象与Fe离子间距离的缩短及反铁磁耦合作用增强有关.
关键词:
直流磁控共溅射
氮化铝薄膜
结构
磁性 相似文献
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The field emission(FE) characteristics of nano-structured carbon films(NSCFs) are investigated.The saturation behaviour of the field emission current density found at high electric field E cannot be reasonably explained by the traditional Fowler-Nordheim(F-N) theory.A three-region E model and the curve-fitting method are utilized for discussing the FE characteristics of NSCFs.In the low,high,and middle E regions,the FE mechanism is reasonably explained by a modified F-N model,a corrected space-charge-limited-current(SCLC) model and the joint model of F-N and SCLC mechanism,respectively.Moreover,the measured FE data accord well with the results from our corrected theoretical model. 相似文献
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