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Single shot spin readout using a cryogenic high-electron-mobility transistor amplifier at sub-Kelvin temperatures

Applied Physics Letters

Tracy, Lisa A.; Luhman, Dwight R.; Carr, Stephen M.; Bishop, N.C.; Ten Eyck, Gregory A.; Pluym, Tammy P.; Wendt, J.R.; Lilly, Michael L.; Carroll, Malcolm

We use a cryogenic high-electron-mobility transistor circuit to amplify the current from a single electron transistor, allowing for demonstration of single shot readout of an electron spin on a single P donor in Si with 100 kHz bandwidth and a signal to noise ratio of ∼9. In order to reduce the impact of cable capacitance, the amplifier is located adjacent to the Si sample, at the mixing chamber stage of a dilution refrigerator. For a current gain of ∼ 2.7 × 10 3, the power dissipation of the amplifier is 13 μW, the bandwidth is ∼ 1.3 MHz, and for frequencies above 300 kHz the current noise referred to input is ≤ 70 fA/ Hz. With this amplification scheme, we are able to observe coherent oscillations of a P donor electron spin in isotopically enriched 28Si with 96% visibility.

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TYPE Journal Article YEAR 2016
DOIOSTIScopus

Nuclear-driven electron spin rotations in a single donor coupled to a silicon quantum dot

Science

Carroll, Malcolm; Harvey-Collard, Patrick; Jacobson, Noah T.; Rudolph, Martin R.; Dominguez, Jason J.; Ten Eyck, Gregory A.; Wendt, J.R.; Pluym, Tammy P.; Laros, James H.; Lilly, Michael L.; Pioro-Ladriere, Michel

Silicon chips hosting a single donor can be used to store and manipulate one bit of quantum information. However, a central challenge for realizing quantum logic operations is to couple donors to one another in a controllable way. To achieve this, several proposals rely on using nearby quantum dots (QDs) to mediate an interaction. In this work, we demonstrate the coherent coupling of electron spins between a single 31 P donor and an enriched 28 Si metal-oxide-semiconductor few-electron QD. We show that the electron-nuclear spin interaction on the donor can drive coherent rotations between singlet and triplet electron spin states of the QD-donor system. Moreover, we are able to tune electrically the exchange interaction between the QD and donor electrons. Furthermore, the combination of single-nucleus-driven rotations and voltage-tunable exchange provides every key element for future all-electrical control of spin qubits, while requiring only a single QD and no additional magnetic field gradients

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TYPE Journal Article YEAR 2016
DOIOSTI

Silicon Quantum Dots with Counted Antimony Donor Implants

Sandia journal manuscript; Not yet accepted for publication

Singh, Meenakshi S.; Pacheco, Jose L.; Perry, Daniel L.; Ten Eyck, Gregory A.; Wendt, J.R.; Pluym, Tammy P.; Dominguez, Jason J.; Manginell, Ronald P.; Luhman, Dwight R.; Bielejec, Edward S.; Lilly, Michael L.; Carroll, Malcolm

Deterministic control over the location and number of donors is crucial to donor spin quantum bits (qubits) in semiconductor based quantum computing. A focused ion beam is used to implant close to quantum dots. Ion detectors are integrated next to the quantum dots to sense the implants. The numbers of ions implanted can be counted to a precision of a single ion. Regular coulomb blockade is observed from the quantum dots. Charge offsets indicative of donor ionization, are observed in devices with counted implants.

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TYPE Journal Article YEAR 2015
OSTIOSTI

Multi-qubit gates protected by adiabaticity and dynamical decoupling applicable to donor qubits in silicon

Physical Review. B, Condensed Matter and Materials Physics

Witzel, Wayne W.; Muller, Richard P.; Carroll, Malcolm

In this paper, we present a strategy for producing multiqubit gates that promise high fidelity with minimal tuning requirements. Our strategy combines gap protection from the adiabatic theorem with dynamical decoupling in a complementary manner. Energy-level transition errors are protected by adiabaticity and remaining phase errors are mitigated via dynamical decoupling. This is a powerful way to divide and conquer the various error channels. In order to accomplish this without violating a no-go theorem regarding black-box dynamically corrected gates [Phys. Rev. A 80, 032314 (2009)], we require a robust operating point (sweet spot) in control space where the qubits interact with little sensitivity to noise. There are also energy gap requirements for effective adiabaticity. We apply our strategy to an architecture in Si with P donors where we assume we can shuttle electrons between different donors. Electron spins act as mobile ancillary qubits and P nuclear spins act as long-lived data qubits. Furthermore, this system can have a very robust operating point where the electron spin is bound to a donor in the quadratic Stark shift regime. High fidelity single qubit gates may be performed using well-established global magnetic resonance pulse sequences. Single electron-spin preparation and measurement has also been demonstrated. Thus, putting this all together, we present a robust universal gate set for quantum computation.

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TYPE Journal Article YEAR 2015
DOIOSTI
Results 101–125 of 333
Results 101–125 of 333