"Anisotropic superconducting gaps in YNi 2 B 2 C: A first-principles investigation"
"Anisotropic superconducting gaps in YNi 2 B 2 C: A first-principles investigation"
复制标题
“YNi 2 B 2 C 中的各向异性超导间隙：第一性原理研究”
DOI：
10.1103/physrevb.95.054506
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发表时间：
2017
影响因子：
3.7
通讯作者：
and S Tsuneyuki
中科院分区：
文献类型：
--
作者：
M Kawamura;R Akashi;and S Tsuneyuki
我们在超导体密度泛函理论的框架下计算了超导隙和态的准粒子密度，以研究这种材料中高各向异性超导隙的起源。计算得到的声子频率、态准粒子密度和转变温度与实验结果吻合较好。通过对超导隙的计算和轨道特性分析，得出费米表面的轨道特性变化是各向异性隙的关键因素。由于主要由铌轨道组成的电子态与声子的耦合较弱，导致相应态的超导隙函数被抑制，从而导致实验中观察到的各向异性。这些结果为提高硼碳化物族材料的转变温度提供了线索。
We calculate superconducting gaps and quasiparticle density of states ofin the framework of the density functional theory for superconductors to investigate the origin of highly anisotropic superconducting gaps in this material. Calculated phonon frequencies, the quasiparticle density of states, and the transition temperature show good agreement with experimental results. From our calculation of superconducting gaps and orbital character analysis, we establish that the orbital character variation of the Fermi surface is the key factor of the anisotropic gap. Since the electronic states that consist of mainly Niorbitals couple weakly with phonons, the superconducting gap function is suppressed for the corresponding states, which results in the anisotropy observed in the experiments. These results are hints to increase the transition temperature of materials in the borocarbide family.