Eric Jutzi

Large spin-orbit coupling for holes in Ge/Si nanostructures allows for ultrafast electrical manipulation of spins in quantum dots [1]. However, the large coupling also limits coherence due to charge noise. The ability to tune the strength of the spin-orbit interaction over a large range via gate voltages therefore promises a switch between fast operations and an idling state that is less sensitive to charge noise. Obtaining and tuning such a large spin-orbit coupling requires strong confinement in two dimensions [2]. While this has been demonstrated in Ge nanowires, it has yet to be achieved in lateral quantum dots in Ge/SiGe heterostructures. By doing that one could take advantage of this clean 2D platform that is also promising for scaling up [3].

We aim to demonstrate this control over the spin-orbit coupling in a strained germanium quantum well by designing and fabricating a gate layout that allows for precise control of the dot shape.

[1] Froning, F.N.M. et al. Nat. Nanotechnol. 16, 308–312 (2021)
[2] Bosco, S. et al. Phys. Rev. B 104, 115425
[3] Lodari, M. et al. Appl. Phys. Lett. 120, 122104 (2022)