As technologies rapidly evolve, materials with targeted properties become top priorities. This has generated a paradigm shift emphasized in the Synthesis and Transformative Manufacturing BRN reports: how on-demand modifications in atomic structure convert to pre-designed properties. The FWP goal is to build multi-component atomic scale structures with unusual precision, so structure-properties expectations are validated. The success hinges in placing atoms at specific locations and tuning atomistic processes (diffusion, nucleation). Two projects are pursued:
- (i) Intercalated metals (starting with Pb) under graphene on SiC (Gr/SiC) to synthesize 2-d quantum materials and control nucleation and growth on top, by tuning the kinetic barriers with metals below. Sub-surface metals can also order forming Moiré patterns, which is another way to modify the band structure, based on chemical bonding and not mechanical stacking.
- (ii) To enhance the yield of on-surface chemical reactions and increase the length of Nanographenes (NGs) by synthesizing them on intercalated Gr/SiC or on metal oxides. NG growth initially involves the deposition of precursors which convert to sp2 bonded materials. Both types of substrates are weakly coupled to NGs so their anticipated properties are not affected. However, understanding growth on weakly interacting substrates is challenging and limited. The kinetic barriers are inherently low and require fine balance between competing atomistic processes.
In both projects characterization is performed within the FWP: of the morphology with surface diffraction, STM, of spectroscopy with STS, of structure stability with DFT, and in collaboration using ARPES.
Project Members:
Principal Investigator: Michael Tringides
Co-PIs: Marek Kolmer, Linlin Wang
Scientific Support Staff: Yong Han
Postdoc: Shen Chen