Engineering a Robust Flat Band in III-V Semiconductor Heterostructures

Electron states in semiconductor materials can be modified by quantum confinement. Adding to semiconductor heterostructures the concept of lateral geometry offers the possibility to further tailor the electronic band structure with the creation of unique flat bands. Using block copolymer lithography, we describe the design, fabrication, and characterization of multiorbital bands in a honeycomb In0.53Ga0.47As/InP heterostructure quantum well with a lattice constant of 21 nm. Thanks to an optimized surface quality, scanning tunnelling spectroscopy reveals the existence of a strong resonance localized between the lattice sites, signature of a p-orbital flat band. Together with theoretical computations, the impact of the nanopatterning imperfections on the band structure is examined. We show that the flat band is protected against the lateral and vertical disorder, making this industry-standard system particularly attractive for the study of exotic phases of matter.

Automated summary

Electron states in semiconductor materials can be modified by quantum confinement, and the concept of lateral geometry in semiconductor heterostructures can further tailor the electronic band structure. By utilizing block copolymer lithography, a honeycomb In0.53Ga0.47As/InP heterostructure with multiorbital bands has been designed, fabricated, and characterized, revealing the existence of a p-orbital flat band. The protection of the flat band against lateral and vertical disorder makes this system particularly attractive for studying exotic phases of matter.