Strain relief and island shape evolution in heteroepitaxial metal growth

Stepanyuk, V. S.; Бажанов, Д. И.; Баранов, А. Н.; Hergert, W.; Dederichs, P. H.; Kirschner, J.

doi:10.1103/physrevb.62.15398

Cited by 85 publications

(88 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although evidenced for a particular system, this result confirms the predictions on mesoscopic relaxation [3,16]. Our results give a clear evidence that the surface-states electrons on nanoislands are significantly affected by local atomic structure.…”

supporting

confidence: 79%

See 1 more Smart Citation

Size-Dependent Surface States of Strained Cobalt Nanoislands on Cu(111)

et al. 2007

Self Cite

View full text Add to dashboard Cite

Low-temperature scanning tunneling spectroscopy over Co nanoislands on Cu(111) showed that the surface states of the islands vary with their size. Occupied states exhibit a sizeable downward energy shift as the island size decreases. The position of the occupied states also significantly changes across the islands. Atomic-scale simulations and ab inito calculations demonstrate that the driving force for the observed shift is related to size-dependent mesoscopic relaxations in the nanoislands.PACS numbers: 73.20.At, It was recognized quite early that metallic particles exhibit unique properties that differ significantly from their bulk counterparts [1]. Nanoislands grown on metal surfaces, in particular, have been a matter of intense research for decades in view of prospective applications in a vast variety of domains ranging from magnetoelectronics, catalysis, optoelectronics, to data storage technology. The electronic, magnetic and chemical properties of a nanoisland are governed by the size, shape and structure of the island. These, in turn, are profoundly influenced by the lattice mismatch with the metal substrate and, for heteroepitaxial systems, also by the bonding interactions in the island/substrate interface (ligand effects). Metal islands tend to adopt the lattice parameter of the underlying surface [2], and as a consequence the bond lengths between the metal atoms in the supported nanoisland are different than those in the parent metals, resulting in changes due to strain. A theoretical study on homoepitaxial double layer Cu islands on Cu(111) [3], has shown that the strain produces an inhomogeneous distribution of bond lengths over the nanoisland, the average bond length varying with island size. The nanoislands also locally distort the surface and induce a displacement pattern in the substrate which affects the diffusion of atoms and, ultimately, the growth of the nanoislands.Despite these studies, our knowledge of how strain affects the properties of a metallic nanoisland, especially the electronic states, remains very limited. The fundamental problem of the change in energy upon lattice distortion in solids has first been addressed by J. Friedel within a simple model [4], and latter on extended to various problems of lattice contractions at metal surfaces and clusters [5]. On the same lines, it has been shown for thin films that strain effects, along with ligand effects, can cause a shift of the surface d band [6,7,8], resulting in chemical properties that are significantly different from those of the pure overlayer metal. Recently, a modification of electronic states due to a local strain field induced by a nanopattern formation has been observed for Cu(100) covered with N atoms [9].In this Letter, we specifically focus on the interplay between strain-induced structural relaxations and the surface states of Co nanoislands on Cu(111). These nanoislands constitute a reference system that has been extensively investigated by Scanning Tunneling Microscopy/Spectroscopy (STM/STS) [10,11,12,13,14]. By ...

show abstract

supporting

confidence: 79%

“…The relaxed atomic configurations have been obtained by means of ab initio fitted many-body potentials formulated in the second moment approximation of the tight-binding theory [3,16,17]. Perfectly triangular unfaulted bilayer Co islands with sizes ranging from 4 nm up to 30 nm were studied.…”

mentioning

confidence: 99%

Size-Dependent Surface States of Strained Cobalt Nanoislands on Cu(111)

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, recent ab initio calculations of the structure of mesoscale islands in several systems with minimal bulk strain, specifically Co/Cu(100) [37,40], Co/Cu(111) [41], and Cu/Cu(111) [38], show that bulk-strain considerations are insufficient to understand the physics associated with low-coverage islands. Experimental stress measurements of Fe and Ni overlayers on W(110) confirm this idea [91,92].…”

Section: Pd-island-w Interactionsmentioning

confidence: 99%

“…Recently, more subtle overlayer-induced effects have been investigated. For example, studies of overlayer mesoscopic islands show that an island can induce substantial elastic strain in the surrounding substrate atoms [37][38][39]. These island-induced strains can influence adatom diffusion [40,41], which can subsequently impact island growth and morphology.…”

Section: Introductionmentioning

confidence: 99%

Core-level spectroscopy of the Pd/W(110) interface: Evidence of long-range Pd-island–W interactions at submonolayer Pd coverages

et al. 2009

View full text Add to dashboard Cite

We have measured W 4f 7/2 core-level photoemission spectra from W(110) in the presence of Pd overlayers for coverages up to ∼1 pseudomorphic monolayer (ML). At coverages close to 0.05 ML a striking change in the W core-level spectrum is observed, which we interpret as indicating a long-range lateral effect of 2D Pd islands upon the W electronic structure in both the first and second W layers. As the coverage increases the long-range effect weakens and finally vanishes near 0.85 ML. Above this coverage the W spectra are typical for a W-based bimetallic interface, with the first-layer W atoms exhibiting a small interfacial core-level shift (−95 ± 5 meV) compared to the bulk atoms.

show abstract

“…This semi-empirical model, based on the second moment tightbinding approximation, was previously used to find strain relief and shape evolution for a Co island on Cu surface. 40 Here, we use the model to calculate the displacements of atomic positions around the step edge. These displacements (magnified by a factor of 30) are depicted for the Co(4/3) step in Fig.…”

mentioning

confidence: 99%

Magnetic anisotropy of vicinal (001) fcc Co films: Role of crystal splitting and structure relaxation in the step-decoration effect

Cinal

Umerski

2006

Phys. Rev. B

View full text Add to dashboard Cite

The uniaxial in-plane magnetic anisotropy (UIP-MA) constant is calculated for a single step on the (001) surface of fcc Co(N ) films. The calculations are done for both an undecorated step and the step decorated with one or more, up to 7, Cu wires. Our objective is to explain the mechanisms by which the decoration decreases the UIP-MA constant, which is the effect observed experimentally for ultrathin Co films deposited on vicinal (001) Cu surfaces and can lead to reorientation of magnetization within the film plane. Theoretical calculations performed with a realistic tight-binding model show that the step decoration changes the UIP-MA constant significantly only if the splitting between the on-site energies of various d-orbitals is included for atoms located near the step edge. The local relaxation of atomic structure around the step is also shown to have a significant effect on the shift of the UIP-MA constant. The influence of these two relevant factors is analyzed further by examining individual contributions to the UIP-MA constant from atoms around the step. The magnitude of the obtained UIP-MA shift agrees well with experimental data. It is also found that an additional shift due to possible charge transfer between Cu and Co atoms is very small.

show abstract

Strain relief and island shape evolution in heteroepitaxial metal growth

Cited by 85 publications

References 27 publications

Size-Dependent Surface States of Strained Cobalt Nanoislands on Cu(111)

Size-Dependent Surface States of Strained Cobalt Nanoislands on Cu(111)

Core-level spectroscopy of the Pd/W(110) interface: Evidence of long-range Pd-island–W interactions at submonolayer Pd coverages

Magnetic anisotropy of vicinal (001) fcc Co films: Role of crystal splitting and structure relaxation in the step-decoration effect

Contact Info

Product

Resources

About