Coherent control of trapped-charge induced resonances in a field-effect transistor

Trapped charges at oxide interfaces in field effect transistors are well known sources of noise and generally degrade the device performance. At low temperatures, operating in the sub-threshold regime, conduction electrons can be confined to percolation pathways [1]. The scattering potential produced by trapped charge can then have a dramatic effect on the conductance, normally observed as random telegraph noise [2]. Here we show that it is possible to coherently excite the trapped electrons with microwave fields, which induce polarization fields that interact with the percolating electrons, measured as high-quality resonances (Q ~ 10
⁴
- 10
⁵
) in the transistor current. Implementing single-shot measurements gives the possibility to study the dynamics of the trapped electrons, and using a standard Ramsey protocol, coherent control is achieved. Given the long coherence times observed (T
₂
~ 10 μs) and since each resonance can be addressed independently in frequency space, the possibility to use such systems as quantum memories or quantum bits is discussed.