Effects of varying compressive biaxial strain on the hydrogen uptake of thin vanadium (001) layers

The hydrogen uptake of asymmetric Fe/V (001) superlattices with L Fe / L V = 3/16 monolayers and 3/10 monolayers was investigated by resistometric methods. The hydrogen distribution and the enthalpy of solution were simulated using a diffusion model and calculated H-H interaction energies. It was found that the strain state of the V lattice strongly influenced the H-H interaction. The hydrogen-depleted interface region in the V layers was populated at lower concentrations than in previously studied symmetric samples, which implied that the energy difference between interior and interface regions was lowered. The V-H binding energy was found to be up to 60 meV higher than in the symmetric superlattices.