Berry phase induced valley level crossing in bilayer graphene quantum dots

2019 ◽  
Vol 99 (12) ◽  
Author(s):  
Zhe Hou ◽  
Yan-Feng Zhou ◽  
X. C. Xie ◽  
Qing-Feng Sun
Keyword(s):  
Quantum Dots ◽  
Berry Phase ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene ◽  
Level Crossing

scholarly journals Visualization and Control of Single-Electron Charging in Bilayer Graphene Quantum Dots

Nano Letters ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 5104-5110 ◽  
Author(s):  
Jairo Velasco ◽  
Juwon Lee ◽  
Dillon Wong ◽  
Salman Kahn ◽  
Hsin-Zon Tsai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene ◽  
Single Electron ◽  
And Control

scholarly journals Energy levels of hybrid monolayer-bilayer graphene quantum dots

2016 ◽  
Vol 93 (16) ◽  
Author(s):  
M. Mirzakhani ◽  
M. Zarenia ◽  
S. A. Ketabi ◽  
D. R. da Costa ◽  
F. M. Peeters
Keyword(s):  
Quantum Dots ◽  
Energy Levels ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene

scholarly journals Recent progresses of quantum confinement in graphene quantum dots

2021 ◽  
Vol 17 (3) ◽  
Author(s):  
Si-Yu Li ◽  
Lin He
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Bound States ◽  
Berry Phase ◽  
Graphene Quantum Dots ◽  
Bound State ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Dirac Fermions ◽  
Tunneling Microscopy

AbstractGraphene quantum dots (GQDs) not only have potential applications on spin qubit, but also serve as essential platforms to study the fundamental properties of Dirac fermions, such as Klein tunneling and Berry phase. By now, the study of quantum confinement in GQDs still attract much attention in condensed matter physics. In this article, we review the experimental progresses on quantum confinement in GQDs mainly by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). Here, the GQDs are divided into Klein GQDs, bound-state GQDs and edge-terminated GQDs according to their different confinement strength. Based on the realization of quasi-bound states in Klein GQDs, external perpendicular magnetic field is utilized as a manipulation approach to trigger and control the novel properties by tuning Berry phase and electron-electron (e-e) interaction. The tip-induced edge-free GQDs can serve as an intuitive mean to explore the broken symmetry states at nanoscale and single-electron accuracy, which are expected to be used in studying physical properties of different two-dimensional materials. Moreover, high-spin magnetic ground states are successfully introduced in edge-terminated GQDs by designing and synthesizing triangulene zigzag nanographenes.

scholarly journals Magnetic field dependence of energy levels in biased bilayer graphene quantum dots

2016 ◽  
Vol 93 (8) ◽  
Author(s):  
D. R. da Costa ◽  
M. Zarenia ◽  
Andrey Chaves ◽  
G. A. Farias ◽  
F. M. Peeters
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Field Dependence ◽  
Magnetic Field Dependence ◽  
Energy Levels ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene

scholarly journals Visualization and Manipulation of Bilayer Graphene Quantum Dots with Broken Rotational Symmetry and Nontrivial Topology

Nano Letters ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 8682-8688
Author(s):  
Zhehao Ge ◽  
Frederic Joucken ◽  
Eberth Quezada ◽  
Diego R. da Costa ◽  
John Davenport ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Rotational Symmetry ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene ◽  
Nontrivial Topology

scholarly journals Properties of Bilayer Graphene Quantum Dots for Integrated Optics: An Ab Initio Study

Photonics ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 78
Author(s):  
Majid Ghandchi ◽  
Ghafar Darvish ◽  
Mohammad Kazem Moravvej-Farshi
Keyword(s):  
Quantum Dots ◽  
Absorption Spectra ◽  
Integrated Optics ◽  
Light Absorption ◽  
Near Infrared ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene ◽  
Infrared Range ◽  
Out Of Plane ◽  
Near Infrared Range

Due to their bandgap engineering capabilities for optoelectronics applications, the study of nano-graphene has been a topic of interest to researchers in recent years. Using a first-principles study based on density functional theory (DFT) and thermal DFT, we investigated the electronic structures and optical properties of bilayer graphene quantum dots (GQDs). The dielectric tensors, absorption spectra, and the refractive indexes of the bilayer GQDs were obtained for both in-plane and out-of-plane polarization. In addition, we calculated the absorption spectra via time-dependent DFT (TD-DFT) in the linear response regime. The TDDFT results show that a blue shift occurs in the absorption spectrum, which is consistent with the experimental results. In this investigation, we consider triangular and hexagonal GQDs of various sizes with zigzag and armchair edges. Our simulations show that unlike monolayer GQDs, for which light absorption for out-of-plane polarization occurs in the ultraviolet wavelength range of 85–250 nm, the out-of-plane polarization light absorption peaks in the bilayer GQDs appear in the near-infrared range of 500–1600 nm, similar to those in bilayer graphene sheets. The out-of-plane polarization light absorption peaks in the near-infrared range make bilayer GQDs suitable for integrated optics and optical communication applications.

scholarly journals Charge Detection in Gate-Defined Bilayer Graphene Quantum Dots

Nano Letters ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 5216-5221 ◽  
Author(s):  
Annika Kurzmann ◽  
Hiske Overweg ◽  
Marius Eich ◽  
Alessia Pally ◽  
Peter Rickhaus ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene ◽  
Charge Detection

Twisted Bilayer Graphene Quantum Dots for Chiral Nanophotonics

2020 ◽  
Vol 124 (41) ◽  
pp. 22704-22710
Author(s):  
Nikita V. Tepliakov ◽  
Artem V. Orlov ◽  
Evgeny V. Kundelev ◽  
Ivan D. Rukhlenko
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene ◽  
Twisted Bilayer Graphene
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