BROKEN-SYMMETRY STATES AT SURFACES: THE (tr)ARPES VIEW

We discuss recent high-resolution angle-resolved photoemission (ARPES) and time-resolved ARPES experiments on selected surfaces which illustrate the formation of broken-symmetry ground states of very different nature: i) a Mott insulator in the layered dichalcogenide 1T-TaSe2, and ii) a spin-orbit split state in the non-magnetic surface alloys BiAg2 and PbAg2.