Alloy surface material design through first-principles

基于无经验参数的量子力学计算，我们成功地给出了预测合金表面结构和相稳定性的计算方法，以及具有高结构自由度的合金纳米粒子。我们发展了“网格-增量团簇展开法”，能够准确地估计纳米粒子中的结构和构型相关的自由能，这大大增强了基于第一性原理的方法在合金表面相稳定性方面的适用性。我们还讨论了晶格振动如何影响合金纳米粒子的偏析，并提出了联合自由能增益的新概念，它可以普遍地描述多元体系中具有第一近邻对组成的固溶体的表面合金的晶格振动对溶解度的影响。

Based on quantum mechanics calculation without empirical parameters, we successtully aevelop calculation metnoa for preaicting structure ana phase stability in alloy surfaces as well as alloy nanoparticles with high structural degree of freedom. We develop" Grid-increment cluster expansion" enabling accurate estimation of structure and configuration-dependent free energy in nanoparticle, which significantly enhance applicability of firstprinciples-based approach to alloy surface phase stability. We also address how lattice vibration affects segregation for alloy nanoparticles, and propose new concept of joint free energy gain that can universaly describe lattice vibrational effects on solubility in surface alloys with solid solution composed of first neares neighbor pairs in multicomponent systems.