Quasiparticle dynamics and optical properties of designer van-der-Waals solids

The goal of this project is to prepare new classes of synthetic layered materials in- situ and then to characterize them using spectroscopy.This approach provides a solution to the intense search efforts for materials-on-demand with engineered electronic and optical applications where new functionalities can be induced. The materials are based on an engineered stacking sequence of layers of functionalized graphene, hexagonal boron nitride (BN), molybdenum disulphide (MoS 2)and silicene/germanene allowing for unprecedented control over their physical properties. The proposed material system provides also a new arena to explore condensed matter phenomenasuch as electron correlation and superconductivity. The groundbreaking aspects of this proposal are as follows. (1) Large-area deterministic growth by chemical vapour deposition (CVD) of heterostructures made from graphene, BN and MoS 2. (2) The characterization will be done by a unique combination of angle-resolved photoemission (ARPES) and optical spectroscopy carried out on the same sample. Hence, both, the single- and two-particle excitation spectrum of the same sample can be probed which allows for a complete understanding of the materials ground state and excited state properties. (3) The effects of mechanical strain and hence large pseudomagnetic fields on the electronic band structure will be investigated using ARPES. (4) The effects of alkali metal doping on electron-phonon coupling and the related superconducting gap will be investigated using ARPES and optical spectroscopies. (5) Tunable optical properties as a function of the stacking of layerswill be investigated using optical spectroscopies. The proposal`s feasibility is firmly grounded on the pioneering work of the PIs group on functionalized graphene and the recent ARPES measurements of a CVD grown graphene/BN heterostructure.