We performed the first principles calculations to study the band structures and plasmonic properties of 2D heterostructures with different combinations. Based on these results, we further proposed a general model for the plasmon dispersion in quasi-2D metals and confirmed it with ab initio calculations. In addition, we investigated the structure of stanene grown on Ag(111) surface, and explored the novel structures for group VI elemental 2D materials with DFT calculations. Moreover, utilizing our knowledge on 2D TMDs, we studied the absorption and charge transfer of different gas molecules on 2D WS2 with DFT calculations. Finally, we investigate the modulations of electronic band structures and electron-electron correlations in twisted bilayer systems, in particular, the twisted bilayer hBN.
The main results obtained this project includes:
•2D TMD plasmonics: understanding how plasmons can be tuned in 2D TMD heterstructures, obtaining a general model for plasmon dispersions in quasi-2D matals, and predicting the long-lived and highly-localized plasmons in quasi-2D metals for large wavevectors.
•Novel 2D materials:
oStanene: Identifying the structure of monolayer stanene grown on the Ag(111) surface and confirming the growth of large area stanene layers on the Ag(111) surface.
oSelenene and tellurene: prediction of 2D monolayer structures for group VI elemental materials. These novel 2D materials are also predicted to be interesting 2D topological insulators.
•Gas Sensor: confirming with experimental collaborators that WS2 hybrid material could be a suitable gas sensor material
•Twisted bilayer systems: showing electronic properties of van der Waals materials can be tuned by twisting stackings and proposing twisted hBN could be an ideal platform to study strong correlations and Moire excitions
For exploitation and dissemination, the research results obtained in this project have been presented in several conferences and workshop. The details are listed below:
Conferences:
•2018 APS March meeting, “Square selenene and tellurene: new members of elemental 2D materials with nontrivial topological properties”
•2019 APS March Meeting, “Tuning the electronic structure and electron correlation in 2D twisted massive Dirac system: the case of twisted bilayer hBN”
Workshops:
•2018 International Workshop on synthetic elemental silicene-like materials, Marseille, “New members of elemental 2D materials: square selenene and tellurene” (Invited talk)
•2019 Max Planck Kickoff Meeting, Flatiron Institute, “Electronic properties and correlations in 2D Moire bilayers”
Especially our publication titled "Large area planar stanene epitaxially grown on Ag(1 1 1)" (Junji Yuhara et al 2018) received a lot of attention by the media resulting in 18 press releases in different scientific and popular websites.
The results and internal reports has also been communicated with our collaborators for further exploitations. Our collaboration with the experimental groups on the gas sensor applications with WS2 hybrid materials is a typical example of results and knowledge exploitation in this project.
The ER has also taken part in the 2018 DESY Open Day and Science Night in Hamburg and delivered scientific knowledge and introduced his research to general public and schoolchildren through informal conversations. These activities have been well received.
Research results obtained have been summarized into research papers published or to be published in scientific journals.
