POLARIZABILITY OF A SHALLOW DONOR IN A QUANTUM-WELL WIRE - GEOMETRIC EFFECTS

Polarizability values (alpha(p)) of a shallow donor in a quantum well wire of the GaAs/Ga1-xAlxAs system are computed for wires of square an d rectangular cross sections. It is found that alpha(p) increases as t he well dimension is increased in both these geometries. In the case o f a wire with rectangular cross section (a = L, b = L/2, with a and b along the x and y axes respectively) alpha(p)-values decrease as the a ngle between the direction of the electric field (applied in the xy-pl ane) and the x axis increases. Results are discussed in the light of t he existing literature.