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 ∼1010 cm−2, and typical lenghtscales of isotropically distributed displacements of these charges, δr≤ 1 nm, and identify pairs (ρ,δr) for which the amplitude and shape of the noise spectrum are in good agreement with spectra reconstructed in recent experiments on similar structures.