Scattering of a spinless particle by an asymmetric Hulth{\'e}n potential within the effective mass formalism

Effective mass Klein-Gordon equation for the asymmetric Hulth{\'e}n potential is solved in terms of hypergeometric functions. Results are obtained for the scattering and bound states with the position dependent mass and constant mass, as a special case. In both cases, we derive a condition for the existence of transmission resonance (T=1). We also study how the transmission resonance depends on the particle energy and the shape of the external potential.