Farías D, Kamiński W, Lobo J, Ortega J, Hulpke E, Pérez R, Flores F, Michel E G
Departamento de Física de la Materia Condensada and Instituto Nicolás Cabrera, Universidad Autónoma, 28049 Madrid, Spain.
Phys Rev Lett. 2003 Jul 4;91(1):016103. doi: 10.1103/PhysRevLett.91.016103. Epub 2003 Jul 3.
The phonon dynamics of the Sn/Ge(111) interface is studied using high-resolution helium atom scattering and first-principles calculations. At room temperature we observe a phonon softening at the Kmacr; point in the (sqrt[3]xsqrt[3])R30 degrees phase, associated with the stabilization of a (3x3) phase at low temperature. That phonon band is split into three branches in the (3x3) phase. We analyze the character of these phonons and find out that the low- and room-temperature modes are connected via a chaotic motion of the Sn atoms. The system is shown to present an order-disorder transition.
利用高分辨率氦原子散射和第一性原理计算研究了Sn/Ge(111)界面的声子动力学。在室温下，我们观察到在（√3×√3）R30°相中K点处的声子软化，这与低温下（3×3）相的稳定有关。在（3×3）相中，该声子带分裂为三个分支。我们分析了这些声子的特性，发现低温和室温模式是通过Sn原子的混沌运动连接的。该系统呈现出有序-无序转变。
