Silicene on Zirconium Carbide (111)
Silicene on Zirconium Carbide (111)
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DOI：
10.1021/jp505602c
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发表时间：
2014-10-09
影响因子：
3.7
通讯作者：
Otani, Shigeki
中科院分区：
文献类型：
--
作者：
Aizawa, Takashi;Suehara, Shigeru;Otani, Shigeki
硅单原子层（即硅）在衬底的2 × 2周期中的ZrC（111）表面上形成有序相。第一次，声子色散关系测量使用高分辨率电子能量损失谱（HREELS）上的硅烯片。用从头算密度泛函理论计算了原子结构和声子色散。几乎所有的表面局域声子模都被很好地再现，特别是偶极激活声子模与镜面HREEL谱中的峰很好地对应。优化的原子结构是在Zr封端的ZrC（111）上的畸变硅烯，其中Si-6的根3 x根3晶胞与基底ZrC（111）的2 x 2晶胞一致。在晶胞中，一个Si原子位于Zr衬底的顶部位置上;三个原子位于衬底的桥位置上;并且另外两个原子位于第三层（C）上方和第四层（Zr）上方的3重中空位置上。这种结构在几种金属基板上普遍存在。
A silicon monatomic layer (i.e, silicence) forms an ordered phase on the surface of ZrC(111) in the 2 x 2 preiodicity of the substrate. For the first time, phonon dispersion relations were measured using high-resolution electron energy loss spectroscopy (HREELS) on a silicene sheet. the atomic structure and phonon dispersions were calculated using ab initio density functional theory. Nearly all the surface-localized phonon modes were well reproduced, and especially the dipole-active phonon modes well corresponded to the peaks in the specular HREEL Spectrum. The optimized atomic structure was a distorted silicene on the Zr-terminated ZrC(111), in which the root 3 x root 3 unit cell of Si-6 coincides with the 2 x 2 unit of the substrate ZrC(111). In the unit cell, one Si atom sits on the on-top site of the Zr substrate; three atoms are placed at the bridge sites of the substrate; and two other atoms are on the 3-fold hollow sites above the third layer (C) and above the fourth layer (Zr). This structure is prevalent on several metal substrates.