  We observe that the reflection and transmission coefficients of a particle
within a double, PT symmetric heterojunction with spatially varying mass, show
interesting features, depending on the degree of non Hermiticity, although
there is no spontaneous breakdown of PT symmetry. The potential profile in the
intermediate layer is considered such that it has a non vanishing imaginary
part near the heterojunctions. Exact analytical solutions for the wave function
are obtained, and the reflection and transmission coefficients are plotted as a
function of energy, for both left as well as right incidence. As expected, the
spatial dependence on mass changes the nature of the scattering solutions
within the heterojunctions, and the space-time (PT) symmetry is responsible for
the left-right asymmetry in the reflection and transmission coefficients.
However, the non vanishing imaginary component of the potential near the
heterojunctions gives new and interesting results.
