Abstract By using density functional theory, we have studied vibrational features, Raman activities, and electronic properties of ultrathin hydrogen-passivated diamond nanowires (H-DNWs). Confinement imposes the softening of transverse acoustic modes and the hardening of the low-optical modes. Higher frequencies optical modes are more influenced by the surface termination effect. Surface effect splits transverse (TO) and longitudinal (LO) optical modes with a redshift from the bulk diamond. Electronic inspection shows that the surface terminated hydrogen atoms have the main contribution to the conduction bands of H-DNWs. This causes, contrary to our expectations from the quantum confinement effect, the electronic bandgap of H-DNWs becomes smaller than bulk diamond.

中文翻译：

---

金刚石纳米线的声子和电子特性

摘要 利用密度泛函理论，我们研究了超薄氢钝化金刚石纳米线 (H-DNWs) 的振动特征、拉曼活动和电子特性。限制强加了横向声学模式的软化和低光学模式的硬化。更高频率的光学模式更受表面终止效应的影响。表面效应将横向 (TO) 和纵向 (LO) 光学模式分开，并从大块金刚石中产生红移。电子检查表明，表面封端的氢原子对 H-DNW 的导带有主要贡献。这与我们对量子限制效应的预期相反，这导致 H-DNW 的电子带隙变得小于块状金刚石。