Flat bands are interesting as their high density of states and suppressed kinetic energy result in strongly enhanced electronic correlations, leading to emergent and unconventional ordered states. Here, the authors use photoelectron momentum microscopy to map an isolated flat band in NbOCl2 across the entire Brillouin zone, revealing its tunable quasiparticle band gap and offering a platform for flat-band physics exploration.
- Changhua Bao
- Vincent Eggers
- Rupert Huber
