Abstract
Transition-metal dichalcogenides (TMD) share the same global layered structure, but distinct polymorphs are characterized by different local coordinations of the transition-metal atoms. Here we compared the and families of metallic TMD, both in the bulk and in the two-dimensional forms. By means of first-principles time-dependent density functional calculations of the loss function, we established the direct connection between the low-energy plasmon properties and the crystal-structure symmetry. The different atomic environments affect the electron-hole excitations, which are prominent at low energies, resulting in distinct in-plane plasmon dispersions in the two families. Conversely, the different periodicity of the plasmon reappearance along the axis perpendicular to the layers can be used to distinguish the various crystal structures of TMD.
3 More- Received 30 July 2014
- Revised 16 October 2014
DOI:https://doi.org/10.1103/PhysRevB.90.205128
©2014 American Physical Society