MOiré Superlattices of correlAted dIChalcogenideS – MOSAICS

The recent progress in controlling the stacking of atomic sheets in van der Waals heterostructures has opened up new avenues for manipulating electronic properties by moiré superlattices, i.e. by long-wavelength periodic potential landscapes. In two-dimensional materials, a moiré superlattice, formed by vertically stacking two layered materials with a twist and/or a difference in lattice constant, generally modifies the electronic band structure and can generates low-energy flat subbands in which electron interactions become the dominant energy scale and lead to emergent electronic phases. The MOSAICS project aims at exploring and exploiting the electronic band structures of transition metal dichalcogenides (TMDs) moiré superlattices generated by twist and intercalation-induced lattice mismatch for discovering and controlling new unconventional phases of matter. It has a particular focus on metallic TMDs for which the range of possible new phenomena becomes huge because they already have a finite density of states at the Fermi level and possess, already in their bulk forms, extremely rich electronic phase diagrams. While these fascinating phases of matter have been extensively studied in 3D materials, they need to be revisited at the 2D limit within moiré superlattices because geometrical frustration enhances quantum fluctuations and can lead to a multitude of closely competing states. Also, metal–semiconductor junctions being at the heart of modern electronics and optoelectronics, twist angles at mTMDs /sTMDs interfaces appear as new degrees of freedom for tuning interlayer coupling strengths and band alignments relevant in electronic device applications. MOSAICS relies on a strong development of coupled sample environment and state-of-the-art angle-resolved photoemission.