Two-dimensional materials and heterostructures exhibit correlated phenomena, whose electronic structures are fundamental to the underlying physics. In this talk, I will present our experimental progress on engineering the electronic structure of quantum materials using moiré superlattice potential and time-periodic light fields. In particular, topological flat bands in rhombohedral graphene...
Kagome metals host van Hove points and flat bands, with the resulting nesting effects potentially leading to unconventional CDW states. Using inelastic X-ray scattering, we show that the CDW in KV3Sb5 forms via a continuous softening of phonons to zero energy, similar to transition metal dichalcogenides (such as NbSe2). The soft phonons exhibit a prominent in-plane anisotropy that mirrors the...
The CsCr3Sb5 exhibits superconductivity in close proximity to a density-wave (DW) like ground state at ambient pressure, however details of the DW are still elusive. Using first-principles density-functional calculations, we found its ground state to be a 4×2 altermagnetic spin-density-wave (SDW) at ambient pressure. The magnetic long range order is coupled to the lattice, generating 4a0...
The question of time-reversal symmetry breaking in CsV3Sb5 remains an open and debated topic, with no definitive consensus established to date. Conventional magnetic field-sensitive probes have not conclusively confirmed the presence of time-reversal symmetry-breaking fields. This presentation will provide new insights into this crucial aspect through a study into the optical coherent phonon...
Two-dimensional materials (2DM) and their heterostructures offer tunable electrical and optical properties, primarily modifiable through electrostatic gating and twisting. While electrostatic gating is a well-established method for manipulating 2DM, achieving real-time control over interfacial properties remains a frontier in exploring 2DM physics and advanced quantum device technology....
