About the stability of noble-metal surfaces during VUV-photoemission experiments

The Shockley-type surface state on Ar covered Au(111): High resolution photoemission results and the description by slab-layer DFT calculations

“…The adsorbates were applied slowly at a partial pressure of %3 · 10 À8 mbar at the measurement position and at low temperatures T = 20 K being clearly below the desorption temperature of the Ar monolayer (T des = 30 K) but high enough to avoid accelerated surface degradation at lower temperatures [11,57]. In general, the temperature influences the binding energy and the linewidth [9,12,[58][59][60], but the differences to the data discussed here are negligible for the present investigation.…”

“…Although this indicates a considerable distortion of the surface ordering by the existence of defects, the increase of the intrinsic linewidth C is rather small. A systematic study on the correlations between background intensity at the Fermi energy, the linewidth and integral intensity of Shockley-state is presented elsewhere [11,62].…”

“…In general, the temperature influences the binding energy and the linewidth [9,12,[58][59][60], but the differences to the data discussed here are negligible for the present investigation. The Ar coverage was monitored in real-time by a comparison of the photoemission intensities of the surface state of covered and uncovered areas [11,16]. In addition, we checked the surface quality of the substrates and the coverage procedure by LEED with the sample holder mounted on a closed-cycle refrigerator in the preparation chamber.…”

“…Because of their confinement to the surface they are quasi-two dimensional electronic states and ideal model systems for the investigation of fundamental many body effects in solids, in particular by scanning tunneling microscopy (STM) [3][4][5], and angular resolved photoemission spectroscopy (ARUPS) [6][7][8][9][10][11][12]. Furthermore, surface states are immediately involved in adsorption and chemical processes on surfaces [13] and, on the other hand, are sensitive probes for modifications of the surface [11,[14][15][16][17][18][19][20].…”

Work function studies of rare-gas/noble metal adsorption systems using a Kelvin probe

“…Proof for that is observed surface states after applying the identical preparation procedure to the same samples at the same SCIENTA instrument. 34,35 However, no subsequent work function/surface state measurements were performed; in addition, LEED measurements showed a good single crystal surface for each material.…”