SCATTERING AND RESONANT-TUNNELING THEORY FOR A CYLINDRICAL WELL IN PLANAR STRUCTURES

A two-dimensional atomic scattering theory is developed for scattering of electrons by a circularly symmetric quantum structure in the two-dimensional electron gas. It is found that the scattering cross section oscillates as a function of ka where k is the electron wave vector and a is the radius of the cylindrical potential barrier. If there is a quantum well inside the potential barrier, there appears a series of sharp resonant-tunneling peaks superposed on the original scattering-cross-section curves. The width of the resonant-tunneling peak depends sensitively on the thickness, the height of the potential barrier, and the electron energy.

CALCULATION OF DIELECTRIC-CONSTANTS FOR SEMICONDUCTORS - AN APPLICATION OF ABINITIO PSEUDOPOTENTIAL METHOD

We have used ab initio pseudopotential method to generate basis wavefunctions and eigen energies to carry out first principle calculations of the static macroscopic dielectric constant for GaAs and GaP. The resulted converged random phase approximation (RPA) value is 12.55 and 10.71, in excellent agreement to the experimental value of 12.4 and 10.86, respectively. The inclusion of the exchange correlation contribution makes the calculated result slightly worsen. A convergence test with respect to the number of k points in Brillouin zone (BZ) integration was carried out. Sixty irreducible BZ k points were used to achieve the converged results. Integration with only 10 special k points increased the RPA value by 15%.