Emerging many-body effects in semiconductor artificial graphene with low disorder

Journal Article · 16 August 2018 · Nature Communications

DOI: https://doi.org/10.1038/s41467-018-05775-4 · OSTI ID:1464294

Du, Lingjie ; Wang, Sheng; Scarabelli, Diego; Pfeiffer, Loren N.; West, Ken W.; Fallahi, Saeed; Gardner, Geoff C.; Manfra, Michael J.; Pellegrini, Vittorio; Wind, Shalom J. ; Pinczuk, Aron

Abstract The interplay between electron–electron interactions and the honeycomb topology is expected to produce exotic quantum phenomena and find applications in advanced devices. Semiconductor-based artificial graphene (AG) is an ideal system for these studies that combines high-mobility electron gases with AG topology. However, to date, low-disorder conditions that reveal the interplay of electron–electron interaction with AG symmetry have not been achieved. Here, we report the creation of low-disorder AG that preserves the near-perfection of the pristine electron layer by fabricating small period triangular antidot lattices on high-quality quantum wells. Resonant inelastic light scattering spectra show collective spin-exciton modes at the M-point's nearly flatband saddle-point singularity in the density of states. The observed Coulomb exchange interaction energies are comparable to the gap of Dirac bands at the M-point, demonstrating interplay between quasiparticle interactions and the AG potential. The saddle-point exciton energies are in the terahertz range, making low-disorder AG suitable for contemporary optoelectronic applications.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0010695; SC0006671
• OSTI ID: 1464294
• Alternate ID(s): OSTI ID: 1511485
• Journal Information: Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 9; ISSN 2041-1723
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United Kingdom
• Language: English