RESPONSE FUNCTIONS FOR QUASI-N-DIMENSIONAL (N=2,1,0) ELECTRON-SYSTEMS

We present an exact analytical method to calculate the inverse dielect ric functions for quasi-two-dimensional electron systems (quantum well s), quasi-one-dimensional electron systems (quantum wires) and quasi-z ero-dimensional electron systems (quantum dots). This is done for mult iple subband occupancy within the random-phase approximation. The resu lting expressions for the inverse dielectric functions pave the way to a simpler means of investigating the collective (both intra- and inte rsubband) excitations and constitute a legitimate basis for studying, for example, the energy loss by a fast charged particle to the respect ive systems.