Confinement of spin-0 and spin-1/2 particles in a mixed vector-scalar   coupling with unequal shapes for the potentials
  The Klein-Gordon and the Dirac equations with vector and scalar potentials are investigated under a more general condition, $V_{v}=V_{s} + \mathrm{const.}$ These isospectral problems are solved in a case of squared trigonometric potential functions and bound states for either particles or antiparticles are found. The eigenvalues and eigenfuntions are discussed in some detail. It is revealed that a spin-0 particle is better localized than a spin-1/2 particle when they have the same mass and are subject to the same potentials. 
Luis B. Castro and Antonio S. de Castro