Surface alloy in the c(4 × 4) phase of Pb on Cu(100)

Gauthier, Yves; Moritz, Wolfgang; Hösler, W.

doi:10.1016/0039-6028(95)00872-1

Cited by 45 publications

(30 citation statements)

References 25 publications

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“…The changes in 2-D island coverage from clean CU(1OO) to a surface completely covered with c(4x4) range between 0.50 and 0.56 ML, in good agreement with the LEED I-V model obtained by Gauthier, Moritz, and Hosler [9]. That is, we expect half of an initially flat Cu(l 00) surface to be displaced upward by one CU(1OO) step height because of the Cu displacement caused by Pb.…”

Section: The C(4x4) Phase: Surface Alloyingsupporting

confidence: 72%

“…The interatomic distance between top layer, nearest neighbor Cu and Pb atoms is 2.84A in c(4x4) [9]. From the model of Hosler and Moritz [6] we calculate the comparable spacing would be 2.61A in an unrelaxed c(2x2) alloyed surface.…”

Section: The C(2x2) Phase: Partial Surface De-alloyingmentioning

confidence: 94%

“…A more recent LEED I-V analysis by Gauthier et al [9], including new information from ST!Minvestigations by Nagl et al [14] and Roberts et al [15], provides compelling evidence that the c(4x4) phase is not an overlayer phase, but a surface alloy consisting of Pb chains within the first layer of Cu ( Fig. lb) and where three Pb atoms have substituted for four of the eight c(4x4) Cu atoms.…”

Section: Background On the Pb/cu(100) Systemmentioning

confidence: 99%

“…Previous investigations by low energy electron diffraction (LEED) [1][2][3][4][5][6][7][8][9][10], He atom scattering [11][12][13], scanning tunneling microscopy (STM) [14,15] and Rutherford backscattering [16] have established that Pb grows on CU(1OO) in a prototypical StranskiKrastanov mode with three well-defined ordered structures at submonolayer coverages.…”

Section: Introductionmentioning

confidence: 99%

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Surface morphology changes during Pb deposition on Cu(100): evidence for surface alloyed Cu(100)–c(2×2) Pb

Plass

Kellogg

2000

Surface Science

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e describe the rnicrofabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear. Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is &4°with a spot size of 0.5 mm. INTRODUCTIONMicro-electromechanical systems (MEMS) is a primarily silicon-based technology that brings precision motion to the microscopic scale using batch fabrication processes developed as extensions from the silicon integrated circuit industry. Compared to the macroscopic systems whose functions they emulate, MEMS are smaller, lighter, lower cost, and more efficient (lower power consumption). For many applications, it is desirable to incorporate optical functions with MEMS. This requires a hybrid approach to integrate compound semiconductor-based light emitters and some form of rnicrooptics, e.g., diffractive optical elements (DOES), to create an integrated microsystem.Integrated Microsystems is an emerging technology in which electrical, optical, and mechanical functions are combined at the chip level into compact, lightweight, and [ultimately] low cost modules with performance equal to or even exceeding those of conventional macroscopic systems. The development of integrated rnicrosystems is expected to revolutionize abroad range of fields, extending beyond electro/optomechanical systems to the fields of biology, chemistry and medicine. Just as the integrated circuit combines formerly discrete devices (transistors, resistors, capacitors) onto a single chip with increasing functionality at DISCLAIMERPortions of this document may be illegible in electronic image products.Images are produced from the best available original document. AbstractUsing Low Energy Electron Microscopy (LEEM), we have followed Cu(l 00) surface morphology changes during Pb deposition at different temperatures. Surface steps advance and 2-D islands nucleate and grow as deposited Pb first alloys, and then dealloys, on a 125°C CU(1OO) surface. From LEEM images, we determine how much Cu is being displaced at each stage and find that the amount of material added to the top layer for a complete Pb/Cu(100) c(4x4) reconstruction (a surface alloy) is consistent with the expected c(4x4) Cu content of 0.5 monolayer. However, as the surface changes to the Pb/Cu...

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Section: The C(4x4) Phase: Surface Alloyingsupporting

confidence: 72%

Section: The C(2x2) Phase: Partial Surface De-alloyingmentioning

confidence: 94%

Section: Background On the Pb/cu(100) Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface morphology changes during Pb deposition on Cu(100): evidence for surface alloyed Cu(100)–c(2×2) Pb

Plass

Kellogg

2000

Surface Science

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“…2 According to the model shown in Fig. 1, the c(4x4) phase is a surface alloy in which every other row of Cu atoms is replaced by Pb atoms [2,3]. To form this surface, it is necessary to displace of 0.5 monolayer Cu.…”

Section: Methodsmentioning

confidence: 99%

Mesoscopic Scale Observations of Surface Alloying, Surface Phase Transitions, Domain Coarsening, and 3D Island Growth Pb on Cu(100)

Kellogg¹

2000

Surface Review and Letters

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Low energy electron microscopy (LEEM) is used to investigate the dynamics of Pb overlayer growth on CU(1OO).By following changes in surface morphology during Pb deposition, the amount of Cu transported to the surface as the Pb first alloys into the surface during formation of the c(4x4) phase and subsequently de-alloys during conversion to the c(2x2) phase is measured.We find that the added coverage of Cu during alloying is consistent with the proposed model for the c(4x4) alloy phase, but the added coverage during de-alloying is not consistent with the accepted model for the c(2x2) phase. To account for the discrepancy, we propose that Cu atoms are incorporated in the c(2x2) structure. Island growth and step advancement during the transition from the c(2x2) to c(5~2xd2)R450 structure agrees with this model. We also use the LEEM to identify the order and temperature of the two-dimensional melting phase transitions for the three Pb/Cu(100) surface structures. Phase transitions for the c(5~2x~2)R45°and c(4x4) structures are first-order, but the c(2x2) transition is second order. We determine that rotational domains of the c(5~2xd2)R45°structure coarsen flom nanometer-to micron-sized dimensions with relatively mild heating (-120 C), whereas coarsening of c(4x4) domains requires considerably higher temperatures (-400 C). In studies of three-dimensional island formation, we find that the islands grow asymmetrically with an orientational dependence that is directly correlated with the domain structure of the underlying c(5~2x~2)R45°phase.1

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Atomic‐Scale Insights into Electrode Surface Dynamics by High‐Speed Scanning Probe Microscopy

Magnussen

2019

Chemistry A European J

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Atomic‐scale processes at electrode surfaces in liquid electrolytes are central elemental steps of electrochemical reactions. Detailed insights into the structure of these interfaces can be obtained with in situ scanning tunnelling and atomic force microscopy. By increasing the time resolution of these methods into the millisecond range, highly dynamic processes at electrode surfaces become directly observable. This review gives an overview of in situ studies with video‐rate scanning probe microscopy techniques. Firstly, quantitative investigations into the dynamic behaviour of individual adsorbed atoms and molecules are described. These reveal a complex dependence of adsorbate surface diffusion on potential and co‐adsorbed species and provide data on adsorbate–adsorbate and adsorbate–substrate interactions in a liquid environment. Secondly, results on collective dynamic phenomena are discussed, such as molecular self‐assembly, the dynamics of nanoscale structures, nucleation and growth, and surface restructuring due to phase‐formation processes.

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Surface alloy in the c(4 × 4) phase of Pb on Cu(100)

Cited by 45 publications

References 25 publications

Surface morphology changes during Pb deposition on Cu(100): evidence for surface alloyed Cu(100)–c(2×2) Pb

Surface morphology changes during Pb deposition on Cu(100): evidence for surface alloyed Cu(100)–c(2×2) Pb

Mesoscopic Scale Observations of Surface Alloying, Surface Phase Transitions, Domain Coarsening, and 3D Island Growth Pb on Cu(100)

Atomic‐Scale Insights into Electrode Surface Dynamics by High‐Speed Scanning Probe Microscopy

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