EFFECT OF QUANTUM CONFINEMENT ON IMPURITY HOPPING IN QUANTUM-WELLS

The problem of evaluation of the impurity hopping conductance in quant um wells is discussed, taking account of the impurity position-depende nt shifts of the binding energies and the variation of the localizatio n radii. It is demonstrated that these effects give rise to a temperat ure dependence of the conductance of the form sigma = sigma(o) exp {-( T-o/T)(1/3)}, where the parameter T-o depends on the well width L. Num erical calculations using the variational principle show that this dep endence is strong far strongly compensated samples in the region of L/ alpha less than or equal to 1, where alpha* is the effective Bohr rad ius.