Quasi–one-dimensional electronic state of alkali metal chains assembled on the

We investigate the electronic band dispersion associated to alkali metal chains assembled on the $\chem{InAs(110)}$ surface by angular-resolved photoelectron spectroscopy. The $\chem{Cs}$ and $\chem{K}$ atomic chains induce occupied electronic states with twofold symmetry and narrow bandwidth along the chain direction, showing a quasi–one-dimensional electronic character. The insulating character and the narrow bandwidth of the alkali-induced state suggest the relevance of electron correlation effects in the description of alkali-induced electronic-state dispersion