A CMOS silicon spin qubit

Abstract

Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal–oxide–semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, the second one a quantum dot used for the qubit read-out. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. The demonstrated qubit functionality in a basic transistor-like device constitutes a promising step towards the elaboration of scalable spin qubit geometries in a readily exploitable CMOS platform.

Hole Spin Resonance and Spin-Orbit Coupling in a Silicon Metal-Oxide-Semiconductor Field-Effect Transistor

“…The g-factor does not change significantly in this area, while the exchange energy can change by a factor of 2 depending on V G . The typical linewidth of EDSR is 0.18 GHz, probably limited by the electrical charge noise due to the strong SOI in our device.We expect only a minor contribution of the nuclear spins to the EDSR linewidth due to the small content (4%) of 29-Si, and the p-orbital nature of holes.It is emphasized that our experiment is performed at temperature of 1.6 K, which is over an order of magnitude higher than the usual temperatures of 0.1 K reported in previous works [20][21][22][23][24][25][26]. Performing the experiment at this high temperature is achieved thanks to the large orbital quantization energy of our dots.…”

“…It is emphasized that our experiment is performed at temperature of 1.6 K, which is over an order of magnitude higher than the usual temperatures of 0.1 K reported in previous works [20][21][22][23][24][25][26]. Performing the experiment at this high temperature is achieved thanks to the large orbital quantization energy of our dots.…”

“…The reason is that the larger spin-orbit interaction (SOI) of a hole (-like) spin enables the spin resonance by an oscillatory electric field, instead of a magnetic field, at microwave frequencies under typical sub-Tesla static magnetic fields. Such electrically-driven spin resonance (EDSR) has been demonstrated in III-V devices [20][21][22][23], as well as in Si [24][25][26], while SOI effects in gate-confined Si quantum dots have been investigated in the spin blockade region [27]. However, systematic investigations of EDSR * E-mail address: k-ono@riken.jp † these authors contributed equally to this work under the direct influence of SOI have not been performed in Si, the material that provides an ideal stage for studying SOI due to the minor presence of nuclear spins.…”

Consequences of Spin-Orbit Coupling at the Single Hole Level: Spin-Flip Tunneling and the Anisotropic g Factor

“…Holes in GaAs are also subject to strong Dreselhaus and Rashba spin-orbit interactions, which introduce the coherent spin-flip tunneling [12,13]. In silicon DQDs these interactions are absent, leading to Pauli spin blockade [21][22][23]. On the other hand, early experiments on GaAs DQDs in many-hole regime show the spin-orbit-induced spin-flip transport [25].…”

Level Spectrum and Charge Relaxation in a Silicon Double Quantum Dot Probed by Dual-Gate Reflectometry

“…Device fabrication relies entirely on deep ultra-violet lithography except for one step, based on electron-beam lithography and used in the definition of the two gates, whose spacing is well below optical resolution. 24 Fig. 1a) shows a false color scanning electron micrograph of a typical device.…”