Spin-orbit gap effects on the surface electronic structure of Ag(0 0 1) around M̄

Angle-resolved photoemission spectra of Ag(0 0 1) corresponding to emission from the M̄ point of the surface Brillouin zone have been re-examined. Two surface states are identified which have energies close to the d-band maximum. The 3.7eV binding energy state, which corresponds to a theoretically predicted M̄2 Tamm state, has previously been ascribed to a surface resonance, has odd parity with respect to the (1 0 0) mirror plane and is assigned in this work to a hybridised Shockley state lying in a spin-orbit gap. Hence, the surface electronic structure near the d-band maximum at M̄ is found to parallel that previously determined for Cu(0 0 1).