Variational Calculation for Triangular Quantum Wells Using Modified Trial Wave Function

In calculations involving triangular quantum wells the Fang-Howard variational wave function is widely used because of its simplicity, although it can lead to substantial errors. This can also occur in transport calculations, where the scattering rate, being proportional to the integral of the fourth power of the wave function, depends strongly on the shape of the wave function. A new set of one-parameter wave functions is introduced and the relaxation time is evaluated for short range scatterers. The improved wave function leads up to about 22 per cent increase in the scattering rate, and to a comparable decrease in the relaxation time.