Ground and first excited states. Ground and first excited state energies of the electron (colored lines) as functions of the applied electric field. The calculations are for R1 = 10 nm, R2 = 20 nm, L = 20 nm, and P = 0. The impurity is placed at zi = 0 and ρi = (R1 + R2)/2. The inset shows the corresponding energy difference between the 2s and 1s states.
Barseghyan et al. Nanoscale Research Letters 2012 7:538 doi:10.1186/1556-276X-7-538