论文标题
在温暖的物质状态下有序的Au-Cu合金的晶格稳定性
Lattice stability of ordered Au-Cu alloys in the warm dense matter regime
论文作者
论文摘要
在温暖的致密状态下，电子温度升高到费米温度的相同顺序，元素金属的动态稳定性取决于其电子带结构以及其晶体结构。众所周知，声子硬化发生是由于电子激发引起的增强的内部压力，就像在封闭的简单金属中一样，而声子软化发生在布里鲁因区域的特定点，如人体以人体为中心的立方体金属。在这里，我们研究了L1 $ _0 $和L1 $ _2 $结构中二进制有序合金（AU和CU）的动态稳定性。通过对声子分散剂进行第一原理计算，我们证明了温暖的密集Au-Cu系统显示了声子硬化行为，除了在L1 $ _0 $结构中AUCU点r处的最低频率声子模式。我们表明，当声音模式通过环境条件下的远距离间相互作用稳定下来时，这种声子将因温暖密集物质的短期性质而稳定。
In the warm dense regime, where the electron temperature is increased to the same order of the Fermi temperature, the dynamical stability of elemental metals depends on its electronic band structure as well as its crystal structure. It has been known that phonon hardening occurs due to an enhanced internal pressure caused by electron excitations as in close-packed simple metals, whereas phonon softening occurs at a specific point in the Brillouin zone as in body-centered cubic metals. Here, we investigate the dynamical stability of binary ordered alloys (Au and Cu) in the L1$_0$ and L1$_2$ structures. By performing first principles calculations on phonon dispersions, we demonstrate that warm dense Au-Cu systems show phonon hardening behavior except the lowest frequency phonon mode at point R of AuCu in the L1$_0$ structure. We show that when a phonon mode is stabilized by long-range interatomic interactions at ambient condition, such a phonon will be destabilized by the short-range nature of the warm dense matters.
