Investigation of c(2×2) Phase of Pb and Bi Coadsorption on Cu(001) by Low Energy Electron Diffraction

Abstract

The surface phases formed by coadsorption of Pb and Bi on a single crystal Cu(001) surface have been investigated using low energy electron diffraction (LEED). The complete phase chart is developed after the coadsorption of Pb and Bi with various coverages. Some notable phases obtained are (1×1), c(2×2), c(4×4) and c(9√2×√2). In this study, we have determined the c(2×2) phase. For individual adsorption of both Pb and Bi, we reconfirmed the c(2×2) structure with more accuracy by a tensor LEED analysis that they both occupy the four fold hollow sites. By comparing the structural parameters of coadsorption and individual adsorption, we conclude that the c(2×2) phase of coadsorption is the mixture of separate domains of the c(2×2) phases of Pb and Bi. This study opens a new window of further research into the surface phase determination of coadsorption of Pb and Bi on Cu(001).

Quantitative Multilayer Cu(410) Structure and Relaxation Determined by QLEED

“…The results show A-B contraction, B-C expansion, and no change in C-D (relative to the bulk-truncated (100) interlayer spacing d 0 bulk [100] = 1.75 Å, cf., Table 2). This trend agrees with the surface layer relaxation of Cu(100) 35 . The topmost and the second layers of the Cu(100) contract relative to the bulk-truncated values, compensating for the lower coordination number.…”

“…6.992 Å), while keeping the slab thickness fixed at 56 layers. In a previous study using LEED 35 , we were able to determine the structure of the first four top layers of clean Cu(001), which is ca. 7 Å thick.…”

“…7 Å thick. To account for thermal vibrations, we used a Debye temperature of 230 K, optimized for the top 8 layers of the unit cell (as in previous studies for clean Cu(001) 35 ). Also note that the corresponding relaxations and Pendry reliability factors remain constant for the optimized surface Debye temperature range 175 K to 300 K, while keeping the bulk Debye temperature constant at 343 K.…”

Quantum Computing using Superconducting Qubits: A Review

“…Many techniques have emerged for the implementation of practical quantum computers, like trapped ion computing 32) that offers scalability even at room temperature, semiconductors [33][34][35][36][37][38][39] which owns a fabrication advantage, superconducting circuits [40][41][42][43] nuclear magnetic resonance 44) that provides less molecular diffusion decoherence, silicon [45][46] , heteropolymer quantum computer, and many others. Amongst these, superconducting qubits have emerged to be a potential participant for scalable quantum computing.…”

Role of Building Automation Technology in Creating a Smart and Sustainable Built Environment

“…Buildings are being created in such a way that they provide maximum comfort and ease to the inhabitants while using the least amount of energy possible in this period, where energy management is a major issue for everyone [23][24][25][26][27] . However, despite a significant amount of study on building automation, the management and efficient energy use of buildings and facilities have remained unsolved [28][29][30] . With the advancement in the field of cloud computing combined with the internet of things (IoT), artificial intelligence and machine language (AI/ML), blockchain, real time monitoring, big data, building information modelling (BIM), and digital twin brings a new paradigm shift in automation, interoperability, energy data management, utilization, and smart analysis of buildings [31][32][33][34][35][36][37][38][39][40] .…”