Alloy formation in the Au{111}/Ni system – An investigation with scanning tunnelling microscopy and medium energy ion scattering

Adsorption of (S)-glutamic acid induces segregation of Ni at bimetallic Au/Ni surfaces

“…We recently reported a MEIS study of the growth and annealing behaviour of ultrathin films of Ni on Au{1 1 1} [11]. In summary, initial growth of Ni occurs in 2-D clusters at the elbows of the Au{1 1 1} herringbone reconstruction [16].…”

“…In each case, desorption of H 2 , CO and CO 2 occurs in a single peak with a T max which varies between 490 K and 530 K depending on the starting surface composition. The as-deposited film is known from STM to be relatively rough [11]. Desorption from this surface occurs in a single peak with a T max at 490 K. After annealing the surface to 460 K, the intensity of each desorption trace is reduced and the T max increases to $530 K. Under these conditions the starting surface consists of a flat Ni-rich surface layer [11].…”

“…However, surface alloys have been reported following deposition of Au onto Ni surfaces [8][9][10] and in the reverse system [11,12].…”

Collective effects in physisorbed molecular hydrogen onNi/Au(111)

“…The Ni/Au(111) alloy formation, shown in figure 1(b), agrees well with previous studies in which Ni atoms preferentially place exchange into the Au(111) surface at the elbows of the 22 × √3 herringbone reconstruction. [30] As the Ni coverage increases, islands one atomic layer high grow at these sites, [30][31][32][33] which consist of intermixed Ni and Au as evidenced by apparent height variations on the islands. [32] It is expected that the islands consist of a Ni-Au alloy due to the negative mixing enthalpy of the two metals.…”

Ultra-thin films and surface alloying of Pd on Cu(111) investigated by medium energy ion scattering

“…However, at low scattering angles the palladium and copper peaks tended to overlap, particularly for the thicker films in the threelayer [114] alignment so when necessary the data was extracted by curvefitting the peaks. Each energy channel where the peaks overlapped was fitted by Gaussians and a sigmoid for the background using a routine described elsewhere [11]. The scattering angles were calibrated by projecting the scattering from the deep bulk of the copper crystal and comparing with simulations.…”