Effect of nonhydrostatic pressure on superconductivity of monatomic iodine: An ab initio study
Effect of nonhydrostatic pressure on superconductivity of monatomic iodine: An ab initio study
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非静水压力对单原子碘超导性的影响：从头算研究
DOI：
10.1103/physrevb.79.064518
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发表时间：
2009-02-01
影响因子：
3.7
通讯作者：
Zou, Guangtian
中科院分区：
文献类型：
--
作者：
Duan, Defang;Jin, Xilian;Zou, Guangtian
用第一性原理赝势平面波方法研究了碘单原子相超导转变温度T_c与流体静压和非流体静压的关系。结果表明，在静水压力下，第II相和第III相的${T}_{c}$与实验结果一致，而在静水压力下，第IV相的${T}_{c}$随压力的增加而减小，与实验结果相反。为了探讨实验结果与理论结果差异的原因，我们研究了非流体静压对单原子碘超导电性的影响，发现在各向异性应力作用下，IV相的对称性由面心立方转变为面心正交（fco）。进一步的计算表明，这种fco结构的${T}_{c}$随着压力的增加而增加，与实验结果一致，这主要归因于非流体静压引起的费米能级电子态密度和电子-声子耦合矩阵元的增强.
The dependence of superconducting transition temperature ${T}_{c}$ on hydrostatic and nonhydrostatic pressures for monatomic phases of iodine has been studied by first-principles pseudopotential plane-wave method. It is shown that the ${T}_{c}$ of both phases II and III under hydrostatic pressures are in agreement with the experimental data while the ${T}_{c}$ of phase IV under hydrostatic pressures decreases with increasing pressure, contrary to the experimental results. In order to explore the origin of difference between experimental and theoretical results, we have studied the effect of nonhydrostatic pressure on the superconductivity of monatomic iodine, and found that the symmetry of phase IV changes from face-centered cubic to face-centered orthorhombic (fco) under anisotropic stresses. Further calculations show that the ${T}_{c}$ of this fco structure increases with increasing pressure, in good agreement with the experimental results, which is mainly attributed to the nonhydrostatic pressure-induced enhancement of the electronic density of states at the Fermi level and electron-phonon coupling matrix element $⟨{I}^{2}⟩$.