Scattering states of Dirac particle equation with position dependent   mass under the cusp potential
  We solved the one-dimensional position-dependent mass Dirac equation in the presence of the cusp potential and reported the solutions in terms of the Whittaker functions. We have derived the reflection and transmission coefficients by making use of the matching conditions on the wave functions. The effect of position dependent mass on the reflection and transmission coefficients of the system is duly investigated. 
M. Chabab, A. El Batoul, H. Hassanabadi, M. Oulne, and S. Zare
nucl-th