Atomic and electronic structure determination for a series of Al–Re–Si MI-type 1/1-cubic approximants
Atomic and electronic structure determination for a series of Al–Re–Si MI-type 1/1-cubic approximants
复制标题
一系列 Al-Re-Si MI 型 1/1 立方近似的原子和电子结构测定
DOI：
10.1016/s0925-8388(02)00263-3
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发表时间：
2002
影响因子：
6.2
通讯作者：
U. Mizutani
中科院分区：
文献类型：
--
作者：
T. Onogi;T. Takeuchi;H. Sato;U. Mizutani
麦凯-二十面体型 Al-Re-Si 1/1-立方近似体的晶体结构通过对同步辐射获取的粉末衍射光谱进行 Rietveld 分析来确定。该近似值的电子结构是通过LMTO-ASA方法用实验确定的原子结构计算的。 Al-Re-Si 1/1 立方近似物之一 Al73.6Re17.4Si9 被发现具有无序结构，与其他 1/1 近似物形成鲜明对比。这种无序结构导致电阻率具有正温度系数和相对较低的残余电阻率。我们通过将费米能级的电子态密度、平均费米速度和测量的电阻率代入玻尔兹曼输运方程来评估平均自由程。由此产生的平均自由程在 5 K 下为 58 Å，在室温下为 21 Å，显示出与这种无序复杂化合物的玻尔兹曼输运机制具有良好的一致性。
The crystalline structure of the Mackay-Icosahedral type Al–Re–Si 1/1-cubic approximants was determined by Rietveld analysis on the powder diffraction spectra taken with synchrotron radiation. The electronic structure of this approximant was calculated by the LMTO-ASA method with the experimentally determined atomic structure. One of the Al–Re–Si 1/1-cubic approximants, Al73.6Re17.4Si9, was found to have a disorder-free structure in sharp contrast with other 1/1-approximants. This disorder-free structure leads to a positive temperature coefficient of the electrical resistivity and a relatively low residual resistivity. We evaluated the mean free path by substituting the electronic density of states at the Fermi level, the averaged Fermi velocity and the measured resistivity into the Boltzmann transport equation. The resulting mean free paths of 58 Å at 5 K and 21 Å at room temperature show a good consistency with the Boltzmann transport mechanism for this disorder-free complex compound.