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 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, $\rho \! \sim \! 10^{10}$ cm$^{-2}$, and typical lenghtscales of isotropically distributed displacements of these charges, $\delta r \! \leq \! 1$ nm, and identify pairs $(\rho,\delta r)$ for which the amplitude and shape of the noise spectrum is in good agreement with spectra reconstructed in recent experiments on similar structures.