Near-freely standing Au quantum well states on MoS2(0Â 0Â 0Â 1) surface

Au(1 1 1) thin films grown on MoS2(0 0 0 1) surface exhibit an intense Shockley type surface state along with a set of well-resolved quantum well states/resonances within and outside the MoS2 energy band gap required for full confinement of Au sp electrons. As a function of wave vector parallel to the surface, the quantum well states display low in-plane energy dispersions. These low in-plane dispersions of the Au quantum well states/resonances are consistent with previous Au quantum well state studies as well as for free standing Au films. The small movement of quantum well states towards the Fermi energy upon increasing film thickness is related to small dispersion of Au sp electrons along the ΓL symmetry direction.