2025/12/22 by Abhikbrata Sarkar, Daniel Loss, Sarkar, Abhikbrata +1
Physics and Astronomy · Engineering · #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #Advancements in Semiconductor Devices and Circuit Design
paper · doi:10.48550/arxiv.2512.19785
We study a vertical double quantum dot (DQD) in a Si/Si1-xGex/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 Ev∼250 μeV. As a result, multiple avenues for fast electrical single qubit rotations emerge. An ac electric field gives rise to electric dipole spin resonance (EDSR), while electron spin resonance (ESR) 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 direction, 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.