Designing new, technologically relevant superconductors has long been at the forefront of solid-state physics and chemistry research. However, developing efficient approaches for modeling the thermodynamics of superconducting alloys while accurately evaluating their physical properties has proven to be a very challenging task. To fill this gap, we propose an ab initio thermodynamic statistical method, the Extended Generalized Quasichemical Approximation (EGQCA), to describe off-stoichiometric superconductors. Within EGQCA, one can predict any computationally accessible property of the alloy, such as the critical temperature in superconductors and the electron-phonon coupling parameter, as a function of composition and crystal growth conditions using a few small supercells. Importantly, EGQCA incorporates directly chemical ordering, lattice distortions, and vibrational contributions. As a proof of concept, we applied EGQCA to the well-known Al-doped MgBb2 and to niobium alloyed with titanium and vanadium, showing a remarkable agreement with the experimental data. Additionally, we modeled the near-room temperature sodalite-like Y1−xCaxH6 superconducting solid solution, demonstrating that EGQCA particularly possesses a promising potential for designing in silico high-Tc superhydride alloys. Our approach enables the high-throughput screening of complex superconducting solid solutions, providing valuable insights into these systems' synthesis, thermodynamics, and physical properties.

中文翻译：

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超导合金的 Ab initio 建模


长期以来，设计新的、技术相关的超导体一直处于固态物理和化学研究的前沿。然而，事实证明，开发有效的方法来模拟超导合金的热力学，同时准确评估其物理特性是一项非常具有挑战性的任务。为了填补这一空白，我们提出了一种从头热力学统计方法，即扩展广义准化学近似 （EGQCA），来描述化学计量超导体。在 EGQCA 中，可以使用一些小超胞来预测合金的任何计算可访问特性，例如超导体中的临界温度和电子-声子耦合参数，作为成分和晶体生长条件的函数。重要的是，EGQCA 直接结合了化学排序、晶格畸变和振动贡献。作为概念验证，我们将 EGQCA 应用于著名的 Al-doped MgBb2 以及铌与钛和钒的合金化，显示出与实验数据显着的一致性。此外，我们模拟了接近室温的类似方石的 Y1-xCaxH6 超导固溶体，证明 EGQCA 在设计计算机高 Tc 超氢合金方面特别具有广阔的潜力。我们的方法能够对复杂的超导固体溶液进行高通量筛选，为这些系统的合成、热力学和物理性质提供有价值的见解。