• 文献标题:   Excited States in Bilayer Graphene Quantum Dots
  • 文献类型:   Article
  • 作  者:   KURZMANN A, EICH M, OVERWEG H, MANGOLD M, HERMAN F, RICKHAUS P, PISONI R, LEE Y, GARREIS R, TONG C, WATANABE K, TANIGUCHI T, ENSSLIN K, IHN T
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW LETTERS
  • ISSN:   0031-9007 EI 1079-7114
  • 通讯作者地址:   Swiss Fed Inst Technol
  • 被引频次:   12
  • DOI:   10.1103/PhysRevLett.123.026803
  • 出版年:   2019

▎ 摘  要

We report ground- and excited-state transport through an electrostatically defined few-hole quantum dot in bilayer graphene in both parallel and perpendicular applied magnetic fields. A remarkably clear level scheme for the two-particle spectra is found by analyzing finite bias spectroscopy data within a two-particle model including spin and valley degrees of freedom. We identify the two-hole ground state to be a spin-triplet and valley-singlet state. This spin alignment can be seen as Hund's rule for a valley-degenerate system, which is fundamentally different from quantum dots in carbon nanotubes, where the two-particle ground state is a spin-singlet state. The spin-singlet excited states are found to be valley-triplet states by tilting the magnetic field with respect to the sample plane. We quantify the exchange energy to be 0.35 meV and measure a valley and spin g factor of 36 and 2, respectively.