Simulation of 1 / f charge noise affecting a quantum dot in a Si/SiGe structure

Abstract

Due to presence of magnetic field gradient needed for coherent spin control, dephasing of single-electron spin qubits in silicon quantum dots is often dominated by 1 / f charge noise. We investigate theoretically fluctuations of ground state energy of an electron in gated quantum dot in a realistic Si/SiGe structure. We assume that the charge noise is caused by motion of charges trapped at the semiconductor-oxide interface. We consider a realistic range of trapped charge densities, ρ ∼ 10 10 cm−2, and typical lenghtscales of isotropically distributed displacements of these charges, δ r ≤ 1 nm, and identify pairs ( ρ , δ r ) for which the amplitude and shape of the noise spectrum are in good agreement with spectra reconstructed in recent experiments on similar structures.