Berry phase induced valley level crossing in bilayer graphene quantum dots

Zhe Hou, Yan-Feng Zhou, X. C. Xie, and Qing-Feng Sun
Phys. Rev. B 99, 125422 – Published 14 March 2019

Abstract

We study the confined bound states in circular bilayer graphene quantum dots. Using the semiclassical Einstein-Brillouin-Keller quantization rule, we predict that valley levels inside the quantum dot undergo three stages: splitting, crossing, and recombining when varying the applied magnetic field. This exotic phenomenon originates from the Berry phase, which increases from zero to 2π with the magnetic field and has opposite signs for the two inequivalent valleys. To further confirm this phenomenon, we perform a fully quantum mechanical calculation based on a low-energy continuum model and a real space tight-binding model, and show that the valley effect can be explicitly observed by scanning-tunneling spectroscopy measurements. Moreover, we propose an efficient valley filter device as an application of this valley effect, which can be used to manipulate the valley degree of freedom in valleytronics.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
6 More
  • Received 5 June 2018

DOI:https://doi.org/10.1103/PhysRevB.99.125422

©2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Zhe Hou1, Yan-Feng Zhou1, X. C. Xie1,2,3, and Qing-Feng Sun1,2,3,*

  • 1International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
  • 2Beijing Academy of Quantum Information Sciences, West Bld.#3,No.10 Xibeiwang East Rd., Haidian District, Beijing 100193,China
  • 3Collaborative Innovation Center of Quantum Matter, Beijing 100871, China

  • *sunqf@pku.edu.cn

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 99, Iss. 12 — 15 March 2019

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×