Shell Filling and Trigonal Warping in Graphene Quantum Dots

Garreis, Rebekka; Knothe, Angelika; Tong, Chuyao; Eich, Marius; Gold, Carolin; Watanabe, Kenji; Taniguchi, Takashi; Ihn, Thomas; Ensslin, Klaus; Kurzmann, Annika

doi:10.1103/physrevlett.126.147703

Cited by 33 publications

(40 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We first define our two-level system. Due to spin and valley degrees of freedom in bilayer graphene, the singleparticle orbital states are four-fold degenerate [18,30]. A perpendicular magnetic field, B ⊥ , lifts the degeneracy due to the spin (s) and valley (v) Zeeman effect following E(B ⊥ ) = ± 1 2 g s,v µ B B ⊥ , with the spin g-factor g s , the valley g-factor g v and the Bohr magneton µ B .…”

Section: Pulsed-gate Spectroscopymentioning

confidence: 99%

“…Compared to the mature Si-based technology, the development of quantum devices in graphene is in its infancy. Recent advances in the controllability of individual states in single QDs [17][18][19][20] and double QDs [21,22], as well as the implementation of charge detection [23], enable the realization of spin qubits based on electrostatically defined QDs in bilayer graphene. Major milestones such as qubit manipulation and detection have yet to be achieved to unlock the qubit potential of graphene.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Single-shot readout in graphene quantum dots

Gächter,

Garreis,

Tong

et al. 2021

Preprint

View full text Add to dashboard Cite

Electrostatically defined quantum dots in bilayer graphene offer a promising platform for spin qubits with presumably long coherence times due to low spin-orbit coupling and low nuclear spin density. We demonstrate two different experimental approaches to measure the decay times of excited states. The first is based on direct current measurements through the quantum device. Pulse sequences are applied to control the occupation of ground and excited states. We observe a lower bound for the excited state decay on the order of hundred microseconds. The second approach employs a capacitively coupled charge sensor to study the time dynamics of the excited state using the Elzerman technique. We find that the relaxation time of the excited state is of the order of milliseconds. We perform single-shot readout of our two-level system with a visibility of 87.1%, which is an important step for developing a quantum information processor in graphene.

show abstract

Section: Pulsed-gate Spectroscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single-shot readout in graphene quantum dots

Gächter,

Garreis,

Tong

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…In bilayer graphene (BLG), a band-gap can be opened by an electric field perpendicular to the BLG sheet [16][17][18] . Together with recent advancements in fabrication technology 19 , the quality of state-of-the-art BLG QDs has been raised to such a level that highly tunable QDs 11,12,14,15,[20][21][22][23] can now be fabricated.…”

mentioning

confidence: 99%

“…A thorough understanding of the relevant (1, 1) and (2, 0) states is crucial for interpreting the nature of the blockade. We introduce the recently established level spectrum of one-and two-particle states in single BLG QDs 11,12,14,15,21,22,26,27 , and limit our discussion to the lowest orbital states (the next higher orbital state is > 1.7 meV away, see Supplementary 1 and Supplementary 2).…”

mentioning

confidence: 99%

“…This is neglected for the discussions here, as ∆ SO ∼ 80 µeV 14,15 is not well-resolved in this experiment. A magnetic field splits the spin states by ∆E ↑/↓ = ±g s µ B B/2 in energy, where g s = 2 11,20,21 . Analogously, the valleys K ± couple to a perpendicular magnetic field with ∆E K ± = ±g v µ B B ⊥ /2, linearly in the low-field limit.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Pauli Blockade of Tunable Two-Electron Spin and Valley States in Graphene Quantum Dots

Tong,

Kurzmann,

Garreis

et al. 2021

Preprint

View full text Add to dashboard Cite

Tuning Confined States and Valley G‐Factors by Quantum Dot Design in Bilayer Graphene

Mayer,

Knothe

2023

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

Electrostatically confined quantum dots in bilayer graphene have shown potential as building blocks for quantum technologies. To operate the dots, e.g., as qubits, a precise understanding and control of the confined states and their properties is required. Here, we perform large‐scale numerical characterization of confined quantum states in bilayer graphene dots over an extensive range of gate‐tunable parameters such as the dot size, depth, shape, and the bilayer graphene gap. We establish the dot states’ orbital degeneracy, wave function distribution, and valley g‐factor and provide the parametric dependencies to achieve different regimes. We find that the dot states are highly susceptible to gate‐dependent confinement and material parameters, enabling efficient tuning of confined states and valley g‐factor modulation by quantum dot design.This article is protected by copyright. All rights reserved.

show abstract

Shell Filling and Trigonal Warping in Graphene Quantum Dots

Cited by 33 publications

References 34 publications

Single-shot readout in graphene quantum dots

Single-shot readout in graphene quantum dots

Pauli Blockade of Tunable Two-Electron Spin and Valley States in Graphene Quantum Dots

Tuning Confined States and Valley G‐Factors by Quantum Dot Design in Bilayer Graphene

Contact Info

Product

Resources

About