Single-shot read-out of an individual electron spin in a quantum dot

By J. Elzerman, Ronald Hanson, L. V. Beveren, B. Witkamp, Lieven M. K. Vandersypen, L. Kouwenhoven. Nature, 2004

1,402 citations recorded by the source corpus.

Spin is a fundamental property of all elementary particles. Classically it can be viewed as a tiny magnetic moment, but a measurement of an electron spin along the direction of an external magnetic field can have only two outcomes: parallel or anti-parallel to the field. This discreteness reflects the quantum mechanical nature of spin. Ensembles of many spins have found diverse applications ranging from magnetic resonance imaging to magneto-electronic devices, while individual spins are considered as carriers for quantum information. Read-out of single spin states has been achieved using optical techniques, and is within reach of magnetic resonance force microscopy. However, electrical read-out of single spins has so far remained elusive. Here we demonstrate electrical single-shot measurement of the state of an individual electron spin in a semiconductor quantum dot. We use spin-to-charge conversion of a single electron confined in the dot, and detect the single-electron charge using a quantum point contact; the spin measurement visibility is ∼65%. Furthermore, we observe very long single-spin energy relaxation times (up to ∼0.85 ms at a magnetic field of 8 T), which are encouraging for the use of electron spins as carriers of quantum information.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/8df5085baddeccd9190ff4c0b1ba6152193a8e56

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In Atomic and Molecular Physics, and Optics

In Electrical and Electronic Engineering

Citations in the corpus

Observation of Faraday rotation from a single confined spin (2006, methodology): “, single-spin read-out has only been achieved using transport measurement”
Spin blockade and lifetime-enhanced transport in a few-electron Si/SiGe double quantum dot (2007, background): “, owing in part to the long lifetimes and slow dephasing of electron spins in semiconductor”
Materials challenges and opportunities for quantum computing hardware (2021, methodology): “3A) is used to perform qubit readout primarily by spin-to-charge conversion methods such as Pauli spin blockade (143) or energyselective tunneling (149).”
Scalable gate architecture for a one-dimensional array of semiconductor spin qubits (2016, methodology): “For both single-shot readout of an individual spin [20, 21] and spin-to-charge conversion in double [14] and triple quantum dot qubits [22] this translates to a need for high fidelity charge state readout.”
Nuclear spin physics in quantum dots: an optical investigation (2012, background): “Electron spin relaxation times of the order of milliseconds can then be measured for magnetic fields of the order of a few Tesla (Amasha et al., 2008; Elzerman et al., 2004; Kroutvar et al., 2004).”
Sensing electric fields using single diamond spins (2011, background): “single electron transistors (SE T)[5] has pushed charge sensing to an unprecedented sensitivity of 10 electron charge, being used in low temperature dete ction and scanning applications[2] or as sensors in quantum d evices[6].”
Cryo-CMOS Circuits and Systems for Quantum Computing Applications (2018, background): “, by measuring the resonance frequency of a microwave resonator in the case of transmons [20], or by measuring the impedance of a charge detector, such as a quantum point contact, in the case of spin qubits [21].”
Silicon CMOS architecture for a spin-based quantum computer (2016, methodology): “Gate-based dispersive readout and initialization Two popular methods for spin qubit readout are based on spin to charge conversion: readout based on the Zeeman energy (using a reservoir) [23] and readout based on the singlettriplet energy (via Pauli spin blockade) [24].”
Spin-resolved quantum-dot resonance fluorescence (2008, background): “Controlled exchange interaction between confined electron spins in electrically defined semiconductor QDs [1] has proven its worth for QIS [2] within the last decade through numerous key demonstrations - most notably the coherent manipulation of one- and two-electron spins [3–5], spin readout [6], a”
Optically active quantum dots in monolayer WSe2. (2014, background): “In contrast, electrically-defined single [11] or double QDs [12] hosting one or two excess electrons have been shown to exhibit long spin coherence times together with a clear path towards integrated scalable devices.”