Work

Micromagnet-free operation of electron spin qubits in Si / Si 1 − x Ge x vertical double quantum dots

Year: 2026

Type: article

Abstract: We study a vertical double quantum dot (DQD) in a Si / Si 1 − x Ge x / Si double-well heterostructure for full electrical control of electron Loss-DiVincenzo (LD) spin qubits, using realistic device modeling and numerical simulations. Due to the emerging spin-orbit interaction in the DQD, as well as strain from the gate electrodes, small (percentage range) but finite g -tensor variations emerge. In addition, we find a large valley splitting, on the order of E v ∼ 250 µ eV . As a result, multiple avenues for fast electrical single-qubit rotations emerge. An ac electric field gives rise to electric dipole spin resonance, while electron spin resonance in the presence of an ac magnetic field can be electrically controlled by local gates due to varying g factors in DQDs. We also show that shuttling between neighboring dots, in vertical and horizontal directions, results in ultrafast single-qubit gates of less than a nanosecond. Remarkably, this DQD architecture completely eliminates the need for micromagnets, significantly facilitating the scalability of LD spin qubits in semiconductor foundries.

Source: Physical Review Research

DOI: 10.1103/rsnv-mnlw

Authors: Abhikbrata Sarkar, Daniel Loss

Institutions: University of Basel, King Fahd University of Petroleum and Minerals

Language: English

Topic: Quantum and electron transport phenomena

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,625

Funder: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung