The lattice dynamics of the ordered Au/Cu(111) surface alloy system are investigated, in particular for the low-coverage ordered Cu(111) -$\text{Au}\left(\sqrt{3}\times \sqrt{3}\right)\text{R}30°$ surface alloy structure. The computations are developed using the phase field matching theory (PFMT) and the Green's functions (GF) formalism. Dispersion branches for surface phonons and resonances along the directions of high symmetry $\overline{\Gamma M}$, $\overline{MK}$, and $\overline{K\Gamma }$ of the two-dimensional (2D) surface Brillouin zone (BZ) of the system, are computed. The vibration local densities of states (LDOS) are also determined for representative atomic sites at the surface alloy boundary. The lattice dynamics of the Cu(111)-$\text{Au}\left(\sqrt{3}\times \sqrt{3}\right)\text{R}30°$ surface reveal novel surface phonon and resonance dispersion branches that could be of potential interest for electronic, chemical, and spintronic applications, notably via electron-phonon interactions at this surface.

研究了有序Au / Cu（111）表面合金体系的晶格动力学，特别是对于低覆盖率有序Cu（111）-$\text{金}（\sqrt{3}\times \sqrt{3}）\text{[R}30°$表面合金结构。计算是使用相场匹配理论（PFMT）和格林函数（GF）形式主义开发的。沿高对称方向的表面声子和共振的色散分支$\overline{\Gamma \mathrm{中号}}$， $\overline{\mathrm{中号}ķ}$和 $\overline{ķ\Gamma }$计算系统的二维（2D）表面布里渊区（BZ）的宽度。还确定了表面合金边界处的代表性原子位点的振动局部态密度（LDOS）。Cu（111）-的晶格动力学$\text{金}（\sqrt{3}\times \sqrt{3}）\text{[R}30°$ 表面揭示出新颖的表面声子和共振弥散分支，这可能是电子，化学和自旋电子学应用的潜在兴趣，特别是通过该表面上的电子-声子相互作用。