Unknown locations of two-level fluctuators in Si/SiGe quantum dots

Determine the physical locations of the two-level fluctuators (TLFs) responsible for charge noise in Si/SiGe quantum-dot devices.

Background

Identifying where TLFs reside within Si/SiGe quantum-dot structures (e.g., gate dielectric, SiGe buffer, buffer/quantum well interface, or within the Si quantum well) is crucial for understanding their coupling to gates and developing targeted noise mitigation strategies.

The authors probe gate-voltage sensitivities of TLF switching times to infer coupling strengths, but emphasize that definitive localization remains unresolved, particularly due to complicating factors such as local heating by the sensor dot current.