Lattice Dynamics of the Rhenium and Technetium Dichalcogenides.
Lattice Dynamics of the Rhenium and Technetium Dichalcogenides.
复制标题
DOI：
10.1186/s11671-016-1459-9
复制
发表时间：
2016-12
影响因子：
--
通讯作者：
Hart LS
中科院分区：
文献类型：
--
作者：
Wolverson D;Hart LS
Re和Tc是层状范德华半导体，由于其异常大的晶胞和偏离六方对称性，显示出大量的喇曼活动区中心声子模。因此，它们提供了将面内各向异性引入到基于van der Waals材料的复合异质结构中的可能性，而拉曼光谱通常用于确定它们的面内取向。我们发现第一性原理计算很好地描述了这一族材料的晶格动力学，从而预测了TcS2的区域中心声子频率和拉曼活性。我们考虑了声子模在频率上的分布和它们的原子位移，并根据拉曼频率随硫化物质量的变化统一了对ReS2、TcS2和ReSe2的声子频率和拉曼光谱的理解。
The rhenium and technetium dichalcogenides are layered van der Waals semiconductors which show a large number of Raman-active zone-centre phonon modes as a result of their unusually large unit cells and deviation from hexagonal symmetry. They thus offer the possibility of introducing in-plane anisotropy into composite heterostructures based on van der Waals materials, and Raman spectroscopy is generally used to determine their in-plane orientation. We show that first-principles calculations give a good description of the lattice dynamics of this family of materials and thus predict the zone-centre phonon frequencies and Raman activities of TcS2. We consider the distribution of the phonon modes in frequency and their atomic displacements and give a unified understanding of the phonon frequencies and Raman spectra of ReS2, TcS2 and ReSe2 in terms of the scaling of Raman frequency with the chalcogen mass.