Electrically Tunable Two-Component Exciton Condensate in a Coulomb-Coupled Graphene Trilayer

@misc{zou2026electrically,
  title = {{Electrically Tunable Two-Component Exciton Condensate in a Coulomb-Coupled Graphene Trilayer}},
  author = {Bo Zou and A. Okounkova and Shuaiqing Zhang and Jian Liao and J. Pack and K. Watanabe and T. Taniguchi and Yihang Zeng},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2608.28381},
  eprint = {2608.28381},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.28381},
  note = {CC BY-NC-SA 4.0},
}

TY  - UNPB
TI  - Electrically Tunable Two-Component Exciton Condensate in a Coulomb-Coupled Graphene Trilayer
AU  - Bo Zou
AU  - A. Okounkova
AU  - Shuaiqing Zhang
AU  - Jian Liao
AU  - J. Pack
AU  - K. Watanabe
AU  - T. Taniguchi
AU  - Yihang Zeng
PY  - 2026
DA  - 2026/08/28
PB  - arXiv
DO  - 10.48550/arxiv.2608.28381
UR  - https://arxiv.org/abs/2608.28381
AB  - Multicomponent condensates possess internal phase degrees of freedom unavailable to a single-component condensate, yet their components are rarely controllable in solids. Here we realize a graphene trilayer with negligible interlayer tunnelling in which the layer-specific carrier densities are continuously tuned by electrostatic gating. Quantum-capacitance measurements demonstrate that charge-incompressible quantum Hall states at total filling factors 1 and 2 persist across the full range of layer-filling configurations and continuously connect the three bilayer exciton-condensate limits. This persistence provides evidence for a trilayer excitonic state. Static Hartree-Fock and time-dependent Hartree-Fock calculations yield two independent finite phase-stiffness eigenmodes and two linearly dispersing Goldstone modes, respectively, when all three layers are partially filled, whereas only one phase-stiffness eigenmode and one linear Goldstone mode remain when one layer is unfilled. The stiffness eigenmodes rotate continuously between the two adjacent-layer exciton bases as charge is transferred among the layers, revealing electrical control of the condensate-mode composition. Together, the experimental and theoretical results support the identification of a two-component exciton condensate with a continuously tunable internal structure.
ER  -