Electric Effect of Impurity in Square Quantum Wires

In the presence of an electric field perpendicular to the axes of the wire, the binding energy of shallow donor impurity in finite square quantum well wires is calculated. For different impurity positions and aspect ratios of the wires, we investigate the Stark shift of the 1s-like state energy of the impurity by expanding the wavefunction into a two-dimensional Fourier series and by using the variational scheme. It is found that the electric field breaks down the degeneracy of the states for impurities symmetrically positioned within the structure and leads to red-shift or blue-shift of the impurity Stark energy, respectively. Furthermore, the scaling rule of the binding energy will not be valid for the square quantum well wire under the applied electric field.