• 文献标题:   Theory of Excitons in Gated Bilayer Graphene Quantum Dots
  • 文献类型:   Article
  • 作  者:   SALEEM Y, SADECKA K, KORKUSINSKI M, MIRAVET D, DUSKO A, HAWRYLAK P
  • 作者关键词:   exciton, quantum dot, graphene, twodimensional material, terahertz
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:  
  • 被引频次:   0
  • DOI:   10.1021/acs.nanolett.3c00406 EA MAR 2023
  • 出版年:   2023

▎ 摘  要

We present a theory of excitons in gated bilayer graphene (BLG) quantum dots (QDs). Electrical gating of BLG opens an energy gap, turning this material into an electrically tunable semiconductor. Unlike in laterally gated semiconductor QDs, where electrons are attracted and holes repelled, we show here that lateral structuring of metallic gates results in a gated lateral QD confining both electrons and holes. Using an accurate atomistic approach and exact diagonalization tools, we describe strongly interacting electrons and holes forming an electrically tunable exciton. We find these excitons to be different from those found in semiconductor QDs and nanocrystals, with exciton energy tunable by voltage from the terahertz to far infrared (FIR) range. The conservation of spin, valley, and orbital angular momentum results in an exciton fine structure with a band of dark low-energy states, making this system a promising candidate for storage, detection and emission of photons in the terahertz range.