Interplay between electronic structure and surface phase transition on α-Ga(010)

The interplay between the surface phase transition on α-Ga(010) and the electronic structure was studied by temperature-dependent high-resolution angle-resolved photoemission using synchrotron radiation. The transition causes several changes in the spectral features. Most importantly, it is accompanied by a decrease of spectral intensity around the Fermi level in large fractions of the surface Brillouin zone. Moreover, it leads to a quasidiscontinuous change in the temperature-dependent linewidth of the dangling-bond surface state at $\overline{C}.$ Finally, an electronic state was observed in the low-temperature phase very close to the Fermi level at $\overline{C}.$ We discuss these findings in the context of a surface charge-density wave model. Above the transition temperature, the electronic structure is somewhat reminiscent of the low-temperature phase but it is influenced by strong fluctuations.