共查询到16条相似文献,搜索用时 453 毫秒
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研究了目前已掺杂的铁基砷化物超导体的硬度和电负性与超导电性的关系,发现其有很好的规律性。因此,提出用硬度均衡值和电负性的平均效应值作为掺杂铁基砷化物超导体超导电性的一个判断标准。 相似文献
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秦正龙 《原子与分子物理学报》2006,23(3):555-558
由原子的主量子数、价电子数及价电子能级值定义一个价电子平均能级指数L,它不仅对所有的原子具有优异的选择性,达到唯一性表征,而且与镧系元素的13种理化性质呈现高度的相关性,估算值与实验值都很好吻合. 相似文献
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应用固体与分子经验电子理论系统地研究液态金属池Na||Sb-Pb-Sn电极的价电子结构与热、电性能.研究结果表明:电极合金的价电子结构与其性能密切关联.阴极合金Na1–xIA_x (IA=K, Rb, Cs)的晶格电子随着掺杂量的增加而减少,诱发合金的熔点、结合能随掺杂量的增加而降低. Na离子输运到阳极,与阳极Sb-Sn-Pb形成产物NaSb_3, NaSn, Na15Sn_4, NaPb.其理论熔点与实验相符. NaSb_3的平均晶格电子数最少,开路电压最高.研究表明:对于Na||Sb-Pb-Sn液态金属电池体系而言,晶格电子扮演重要的角色,可以调控电极的热、电性能. 相似文献
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Correlation between electronic structure and energy band in Eu-doped CuInTe_2 semiconductor compound with chalcopyrite structure 下载免费PDF全文
The Eu-doped Cu(In, Eu)Te_2 semiconductors with chalcopyrite structures are promising materials for their applications in the absorption layer for thin-film solar cells due to their wider band-gaps and better optical properties than those of CuInTe_2. In this paper, the Eu-doped CuInTe_2(CuIn_(1-x)Eu_xTe_2, x = 0, 0.1, 0.2, 0.3) are studied systemically based on the empirical electron theory(EET). The studies cover crystal structures, bonding regularities, cohesive energies, energy levels,and valence electron structures. The theoretical values fit the experimental results very well. The physical mechanism of a broadened band-gap induced by Eu doping into CuInTe_2 is the transitions between different hybridization energy levels induced by electron hopping between s and d orbitals and the transformations from the lattice electrons to valence electrons for Cu and In ions. The research results reveal that the photovoltaic effect induces the increase of lattice electrons of In and causes the electric resistivity to decrease. The Eu doping into CuInTe_2 mainly influences the transition between different hybridization energy levels for Cu atoms, which shows that the 3d electron numbers of Cu atoms change before and after Eu doping. In single phase CuIn_(1-x)Eu_xTe_2, the number of valence electrons changes regularly with increasing Eu content,and the calculated band gap E_g also increases, which implies that the optical properties of Eu-doped CuIn_(1-x)Eu_xTe_2 are improved. 相似文献
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通过第一性原理计算研究了具有锯齿状边沿并且具有反铁磁构型的单层石墨纳米带的自旋极化输运.研究发现,在中心散射区同一位置掺入单个B和N原子,尽管对整个体系磁矩的影响完全相同,但对两个自旋分量电流的影响却完全相反.掺B时,自旋向上的电流显著大于自旋向下的电流;而掺N时,自旋向下的电流显著大于自旋向上的电流.这是由于不管掺B还是掺N都将打破自旋简并,使得导带和价带中自旋向上的能级比自旋向下的能级更高.掺B引入空穴,使完全占据的价带变为部分占据,从而自旋向上的能级正好处于费米能级,使得电子透射能力更强、电流更大,而自旋向下的能级则离费米能级较远使电子透射的能力较弱.掺N则引入电子,使得原来全空的导带变为部分占据,从而费米能级穿过导带中自旋向下的能级,使得自旋向下的电子比自旋向上的电子透射能力更强.
关键词:
自旋极化输运
单层石墨纳米带
第一性原理
非平衡格林函数 相似文献
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此文用基于密度泛函理论(DFT)的第一性原理赝势平面波方法系统的计算了Sb、Ce掺杂Mg2Ge的能带结构、态密度以及光学性质,获得了Mg2Ge掺杂Sb后,费米面进入导带,呈现n型导电;Mg2Ge掺杂Ce后,上自旋电子在费米能级附近处的价带和导带有一部分重叠,呈现半金属特性,进入导带电子数目增多,导电性增强. Sb、Ce掺杂Mg2Ge后,其主要吸收峰都小于未掺杂Mg2Ge,在可见光区域的透过率增大;Sb掺入后,在能量低于2.6 eV反射谱出现红移,Ce掺入后Mg2Ge的吸收范围明显宽于本征Mg2Ge;掺杂改善了Mg2Ge对红外光子的吸收等有益结果. 相似文献
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Nesting in a semimetal can lead to an excitonic-insulator state with spontaneous coherence between conduction and valence bands and a gap for charged excitations. We present a theory of the ferromagnetic state that occurs when the density of electrons in the conduction band and holes in the valence band differ. We find an unexpectedly rich doping-field phase diagram and an unusual collective excitation spectrum that includes two gapless collective modes. We predict regions of doping and external field in which phase-separated condensates of electrons and holes with parallel spins and opposing spins coexist. 相似文献