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Epitaxy of Fe3O4 on Si(001) by pulsed laser deposition using a TiN/MgO buffer layer  [PDF]
D. Reisinger,M. Schonecke,T. Brenninger,M. Opel,A. Erb,L. Alff,R. Gross
Physics , 2003, DOI: 10.1063/1.1587885
Abstract: Epitaxy of oxide materials on silicon (Si) substrates is of great interest for future functional devices using the large variety of physical properties of the oxides as ferroelectricity, ferromagnetism, or superconductivity. Recently, materials with high spin polarization of the charge carriers have become interesting for semiconductor-oxide hybrid devices in spin electronics. Here, we report on pulsed laser deposition of magnetite (Fe3O4) on Si(001) substrates cleaned by an in situ laser beam high temperature treatment. After depositing a double buffer layer of titanium nitride (TiN) and magnesium oxide (MgO), a high quality epitaxial magnetite layer can be grown as verified by RHEED intensity oscillations and high resolution x-ray diffraction.
First-principles calculations of step formation energies and step interactions on TiN(001)  [PDF]
C. V. Ciobanu,D. T. Tambe,V. B. Shenoy
Physics , 2004, DOI: 10.1016/j.susc.2005.03.025
Abstract: We study the formation energies and repulsive interactions of monatomic steps on the TiN(001) surface, using density functional total-energy calculations. The calculated formation energy of [100] oriented steps agree well with recently reported experimental values; these steps are shown to have a rumpled structure, with the Ti atoms undergoing larger displacements than the N atoms. For steps that are parallel to [110], our calculations predict a nitrogen (N) termination, as the corresponding formation energy is several hundred meV/\AA \ smaller than that of Ti-terminated steps.
First principles study of interactions between Au and N atoms on SrTiO3 ( 001) surface

Fang Li-Min,

物理学报 , 2011,
Abstract: First principles PWPP calculations based on the density functional theory were carried out to study the microscopic mechanism of the interaction between Au and N atoms on SrTiO3(001) surface. From analysis of the related energies and density of states, it was confirmed that there is clearly a synergy effect between the substitution of N for the surface O atoms and the adsorption of Au atoms on the SrTiO3(001) surface. In other words, the substitution of N atoms for O atoms stabilizes the Au atoms adsorbed on the surface, and the presence of the adsorbed Au atoms can also favor the process of N substitution on the surface.
Chemisorption of Au on Si(001) surface
Chemisorption of Au on Si(001) surface

Wei Shu-Yi,Wang Jian-Guang,Ma Li,

中国物理 B , 2004,
Abstract: The chemisorption of one monolayer of Au atoms on an ideal Si(001) surface is studied by using the self-consistent tight binding linear muffin-tin orbital method. Energies of the adsorption system of a Au atom on different sites are calculated. It is found that the most stable position is A site (top site) for the adsorbed Au atoms above the Si(001) surface. It is possible for the adsorbed Au atoms to sit below the Si(001) surface at the B_1 site(bridge site), resulting in a Au-Si mixed layer. This is in agreement with the experiment results. The layer projected density of states is calculated and compared with that of the clean surface. The charge transfer is also investigated.

Xu yi,Pan Zhen-Ying,Wang Yue-Xia,

物理学报 , 2001,
Abstract: 采用分子动力学方法和混合的Finnis-Sinclain势得到了Cu6团簇的最稳定结构——正八面体结构,模拟了此结构的Cu6团簇在入射能量(Ein)范围为0-30eV/原子下与Cu(001)和Au(001)表面皮秒(ps)级时间内的朴素作用,计算结果表明在此能量范围内,由于荷能团簇原子与表面的相互作用,团簇原子由原来的正八面体Cu6结构演变为fcc结构沉积在衬底表面,随着Ein的增加,团簇原子的穿透深度及与表面原子的交换增加,于能量增加至一阈值,衬底表面观察到空位及间隙子损伤,与Cu表面相比,Cu6在Au表面的损伤阈能略高,得出团簇原子在表面的再构是在很短的时间(ps量级)内发生,在该时间范围级联碰撞对团簇再构起主要作用,本工作支持相关的实验结果,低能团簇束沉积(LECBD)有利于纳米表面的形成,进而改变团簇沉积能量,可控制表面纳米薄膜的结构。
Chemisorption of Fe on Au-passivated Si(001) surface
Chemisorption of Fe on Au-passivated Si(001) surface

Wei Shu-Yi,Wang Jian-Guang,Ma Li,Xia Cong-Xin,Yan Yu-Li,

中国物理 B , 2004,
Abstract: The chemisorption of one monolayer of Fe atoms on a Au-passivated Si(001) surface is studied by using the self-consistent tight-binding linear muffin-tin orbital method. The Fe adatom chemisorption on an ideal Si(001) surface is also considered for comparison. The chemisorption energy and layer projected density of states for a monolayer of Fe atoms on Au-passivated Si(001) surface are calculated and compared with that of the Fe atoms on an ideal Si(001) surface. The charge transfer is investigated. It is found that the most stable position is at the fourfold hollow site for the adsorbed Fe atoms, which might sit below the Au surface. Therefore there will be a Au-Fe mixed layer at the Fe/Au-Si(100) interface. It is found that the adsorbed Fe atoms cannot sit below the Si surface, indicating that a buffer layer of Au atoms may hinder the intermixing of Fe atoms and Si atoms at the Fe/Au-Si(001) interface effectively, which is in agreement with the experimental results.
Deposition of Na Clusters on MgO(001)  [PDF]
M. Baer,P. M. Dinh,L. V. Moskaleva,P. -G. Reinhard,N. Roesch,E. Suraud
Physics , 2010,
Abstract: We investigate the dynamics of deposition of small Na clusters on MgO(001) surface. A hierarchical modeling is used combining Quantum Mechanical with Molecular Mechanical (QM/MM) description. Full time-dependent density-functional theory is used for the cluster electrons while the substrate atoms are treated at a classical level. We consider Na$_6$ and Na$_8$ at various impact energies. We analyze the dependence on cluster geometry, trends with impact energy, and energy balance. We compare the results with deposit on the much softer Ar(001) surface.
From bi-layer to tri-layer Fe nanoislands on Cu3Au(001)  [PDF]
A. Verdini,L. Floreano,F. Bruno,D. Cvetko,A. Morgante,F. Bisio,S. Terreni,M. Canepa
Physics , 2001, DOI: 10.1103/PhysRevB.65.233403
Abstract: Self assembly on suitably chosen substrates is a well exploited root to control the structure and morphology, hence magnetization, of metal films. In particular, the Cu3Au(001) surface has been recently singled out as a good template to grow high spin Fe phases, due to the close matching between the Cu3Au lattice constant (3.75 Angstrom) and the equilibrium lattice constant for fcc ferromagnetic Fe (3.65 Angstrom). Growth proceeds almost layer by layer at room temperature, with a small amount of Au segregation in the early stage of deposition. Islands of 1-2 nm lateral size and double layer height are formed when 1 monolayer of Fe is deposited on Cu3Au(001) at low temperature. We used the PhotoElectron Diffraction technique to investigate the atomic structure and chemical composition of these nanoislands just after the deposition at 140 K and after annealing at 400 K. We show that only bi-layer islands are formed at low temperature, without any surface segregation. After annealing, the Fe atoms are re-aggregated to form mainly tri-layer islands. Surface segregation is shown to be inhibited also after the annealing process. The implications for the film magnetic properties and the growth model are discussed.
First-principles calculations of strontium on Si(001)  [PDF]
Christopher R. Ashman,Clemens J. Foerst,Karlheinz Schwarz,Peter E. Bloechl
Physics , 2003, DOI: 10.1103/PhysRevB.69.075309
Abstract: This paper reports state-of-the-art electronic structure calculations on the deposition of strontium on the technologically relevant, (001) orientated silicon surface. We identified the surface reconstructions from zero to four thirds monolayers and relate them to experimentally reported data. A phase diagram is proposed. We predict phases at 1/6, 1/4, 1/2, 2/3 and 1 monolayers. Our results are expected to provide valuable information in order to understand heteroepitaxial growth of a prominent class of high-K oxides around SrTiO3. The insight obtained for strontium is expected to be transferable to other alkaline earth metals.
Growth Model of Au Films on Ru(001)  [PDF]
E. Canessa,A. Calmetta
Physics , 1992, DOI: 10.1016/0375-9601(92)90330-O
Abstract: In an attempt to find generic features on the fractal growth of Au films deposited on Ru(001), a simple simulation model based on irreversible diffusion-limited aggregation (DLA) is discussed. Highly irregular two-dimensional dentritic islands of Au particles that gradually grow on a larger host lattice of Ru particles and have fractal dimension d_{f}~ 1.70 each, are generated via a multiple had-hoc version of the DLA algorithm for single aggregates. Annealing effects on the islands morphology are reproduced assuming different sticking probabilities at nearest-neighbour lattice sites of Au films on Ru(001). Using simulation data, islands growth are described in analogy to diffusion-limited, precipitate growth with soft impingement of precipities. This leads to analyse thin film island growth kinetics in such fractal systems and to predict a main peak in scattering intensity patterns due to interisland interference. ---------------- Copies upon request to: canessae@itsictp.bitnet
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