First‐principles calculations are performed to investigate the electronic states of 1/1 and 2/1 approximants with the composition Al₁₅Zn₄₀Mg₄₅, which is close to the quasicrystal (QC) Al_14.9Zn_41.0Mg_44.1 in which the superconductivity recently has been discovered. The density of states for the 1/1 approximant shows a wide pseudogap structure near the Fermi level as commonly observed in various approximants of the QCs, whereas those for the 2/1 approximant do not show such a wide pseudogap. Instead of the wide pseudogap, the 2/1 approximant shows a remarkable narrow pseudogap at the Fermi level in contrast to the 1/1 approximant, which shows a shallow hump at the Fermi level within the wide pseudogap. This seems to be consistent with the experimental observation of the electrical resistivity, which increases with decreasing temperature from room temperature down to around the superconducting transition temperature for the 2/1 approximant together with the QC, whereas it monotonically decreases for the 1/1 approximant.

中文翻译：

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基于第一性原理计算的Al-Mg-Zn准晶体的电子态及其近似

进行第一性原理计算，以研究组成为Al ₁₅ Zn ₄₀ Mg ₄₅，与准晶体（QC）Al _14.9 Zn _41.0 Mg _44.1接近的1/1和2/1近似电子态。最近发现了超导性。正如在QC的各种近似物中通常观察到的，1/1近似值的状态密度在费米能级附近显示出宽的伪间隙结构，而2/1近似值的状态密度没有显示出如此宽的伪间隙。代替宽伪间隙，2/1近似值在费米能级上显示出显着的窄伪间隙，而与1/1近似值相反，后者在宽伪间隙内在费米能级上出现了浅驼峰。这似乎与电阻率的实验观察结果一致，电阻率随着温度从室温下降到大约2/1的近似超导转变温度以及QC的增加而增加，而对于1/1近似的电阻率则单调降低。 。