Roughening and melting of Au(110) surfaces

Abstract

The structure of the Au(110) surface was investigated in the temperature range between 60 and 1250 K by the ion channeling and blocking method using an electrostatic energy analyzer. An anomalous temperature dependence of the blocking pattern was found around 680 K which may be caused by a roughening transition. Above 770 K the number of visible atom layers increases faster with increasing temperature, as expected from the temperature dependence of the mean vibration amplitude.The number of observed disordered (110) layers follows a logarithmic growth law as predicted by the premelting theory and molecular dynamics simulations.

Metal-phthalocyanine ordered layers on Au(110): Metal-dependent adsorption energy

“…31 This fact indicates that the single-layer desorption is expected to occur at a higher temperature, incompatible with the Au(110) substrate stability. 28 The VB data of the SLs confirm the strong molecule-substrate interaction, driven mainly by the central metal Fe and Co ions. Since CuPc presents the d z 2 orbital completely filled, at contrast with FePc and CoPc, its interaction with Au(110) is weaker, and as a consequence the CuPc SL desorbs at a lower temperature from the Au(110) surface.…”

“…The CuPc molecular layer presents a desorption peak at 700 K, while not any desorption peak is observed for FePc and CoPc up to 820 K, the maximum annealing temperature compatible with the Au(110) substrate stability. 28 Thus, while the FePc and CoPc SLs remain adsorbed on the Au(110) surface, the CuPc SL desorbs, demonstrating that a different interaction between these MPcs and Au(110) takes place in the SL coverage phase. Since the interaction of the molecules with the substrate is mainly driven by the charge transfer from metal states to the central metal ion, a dependence on the filling of the d-states is expected.…”

“…28 The XPS Fe-2p 3/2 core levels measured after each annealing step, are shown in Fig. 2, right panel.…”

“…6 The higher BE of the b 2g orbital for CoPc than for FePc is due to the higher occupation of the d-orbitals in CoPc with respect to the FePc. 5 The MPc thin films have been annealed at increasing temperatures, the molecular orbital intensity reduces due to multi-layer desorption, which is basically completed for both molecular layers above 600 K. At the highest temperature reachable without affecting the Au crystalline surface (820 K), 28 the typical HOMO of the TF is disappeared, while an energy-shifted orbital is present at about 1 eV for both FePc and CoPc, which we attribute to an interface HOMO (HOMO if ), and a further peak (I 0 ) emerges between the HOMO if and the Fermi level. The HOMO if is at almost the same energy for both FePc and CoPc SLs and it has been attributed to the macrocycle interaction through the π a 1u orbitals with the Au d states.…”

Thermal stability of mesoporous silica-coated gold nanorods with different aspect ratios

“…For non-spherical nanoparticles, a shape transformation into nanospheres 3 can be observed as the nanoparticle reduces its surface energy due to the applied heat. The melting of both spherical and rod-shaped gold nanoparticles can be interpreted in terms of surface melting [22][23][24][25], whereby there is a small difference in the melting temperatures for the different facets [26][27][28]. For gold nanorods the surface melting is accompanied by the transformation into nanospheres, which is explained by Insawa et al in Ref.…”