Spin relaxation in a single-electron graphene quantum dot

Banszerus, L.; Hecker, K.; Möller, S.; Icking, E.; Watanabe, K.; Taniguchi, T.; Volk, C.; Stampfer, C.

doi:10.48550/arxiv.2110.13051

Cited by 2 publications

(10 citation statements)

References 33 publications

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“…As a consequence, a suppression of transport current is observed, typically at bias triangles of a double dot with few carriers, resulting in spin (valley) blockade. Furthermore, dynamics of excited states are also studied using pulsed-gate spectroscopy [192][193][194] . A spin relaxation time exceeding 200 μs has been extracted [193] .…”

Section: / 37mentioning

confidence: 99%

“…Furthermore, dynamics of excited states are also studied using pulsed-gate spectroscopy [192][193][194] . A spin relaxation time exceeding 200 μs has been extracted [193] .…”

Section: / 37mentioning

confidence: 99%

“…For example, the tunneling barrier needs to be sufficiently opaque in the measurement of spin relaxation time, with tunneling rates having typical values of several MHz. This results in a transport current below 1 pA, which is very difficult to be precisely measured [192][193][194] . Meanwhile, particular electron state manipulations require that the electron tunneling can only happen through single-side barrier [222] .…”

Section: Challenges and Opportunitiesmentioning

confidence: 99%

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Gate‐Controlled Quantum Dots Based on 2D Materials

et al. 2022

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Two-dimensional (2D) materials are a family of layered materials exhibiting rich exotic phenomena, such as valleycontrasting physics. Down to single-particle level, unraveling fundamental physics and potential applications including quantum information processing in these materials attracts significant research interests. To unlock these great potentials, gate-controlled quantum dot architectures have been applied in 2D materials and their heterostructures. Such systems provide the possibility of electrical confinement, control, and manipulation of single carriers in these materials. In this review, efforts in gate-controlled quantum dots in 2D materials are presented. Following basic introductions to valley degree of freedom and gate-controlled quantum dot systems, the up-to-date progress in etched and gate-defined quantum dots in 2D materials, especially in graphene and transition metal dichalcogenides, is provided. The challenges and opportunities for future developments in this field, from views of device design, fabrication scheme, and control technology, are discussed. The rapid progress in this field not only sheds light on the understanding of spin-valley physics, but also provides an ideal platform for investigating diverse condensed matter physics phenomena and realizing quantum computation in the 2D limit.

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Section: / 37mentioning

confidence: 99%

“…Furthermore, dynamics of excited states are also studied using pulsed-gate spectroscopy [192][193][194] . A spin relaxation time exceeding 200 μs has been extracted [193] .…”

Section: / 37mentioning

confidence: 99%

Section: Challenges and Opportunitiesmentioning

confidence: 99%

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Gate‐Controlled Quantum Dots Based on 2D Materials

et al. 2022

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“…[33] suffered from this limitation, stating a lower bound of T 1 = 500 ns. To improve on this limitation, we extend the pulsing sequence to four-level pulses with added load and wait phases in which both |↑ and |↓ are pulsed below the bias window [26,34]. The voltage and time for the load phase is chosen such that the time-integral over voltages in one pulse sequence is zero, in order to avoid charging up the bias-tee.…”

Section: Pulsed-gate Spectroscopymentioning

confidence: 99%

“…In order to reach the single-shot readout limit, it is critical for the excited state relaxation time to be longer than the measurement time to resolve a single charging event. We first investigate the relaxation time by measuring the * lisag@phys.ethz.ch current flowing through a QD [24,25], which allows us to extract a lower bound only, similar to previous experiments [26]. In order to study the time dynamics of the excited state beyond the microsecond regime, we add a charge detector to the device design and perform timeresolved measurements of the tunneling events in the QD.…”

Section: Introductionmentioning

confidence: 99%

Single-shot readout in graphene quantum dots

Gächter,

Garreis,

Tong

et al. 2021

Preprint

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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.

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Spin relaxation in a single-electron graphene quantum dot

Cited by 2 publications

References 33 publications

Gate‐Controlled Quantum Dots Based on 2D Materials

Gate‐Controlled Quantum Dots Based on 2D Materials

Single-shot readout in graphene quantum dots

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