{"title":"Probing local moments in nanographenes with electron tunneling spectroscopy","authors":"R. Ortiz , J. Fernández-Rossier","doi":"10.1016/j.progsurf.2020.100595","DOIUrl":"https://doi.org/10.1016/j.progsurf.2020.100595","url":null,"abstract":"<div><p>The emergence of local moments in graphene zigzag edges, grain boundaries, vacancies and sp<sup>3</sup> defects has been widely studied theoretically. However, conclusive experimental evidence is scarce. Recent progress in on-surface synthesis has made it possible to create nanographenes, such as triangulenes, with local moments in their ground states, and to probe them using scanning tunneling microscope (STM) spectroscopy. Here we review the application of the theory of sequential and cotunneling transport to relate the <span><math><mrow><mi>dI</mi><mo>/</mo><mi>dV</mi></mrow></math></span> spectra with the spin properties of nanographenes probed by STM. This approach permits us to connect the <span><math><mrow><mi>dI</mi><mo>/</mo><mi>dV</mi></mrow></math></span><span><span> with the many-body energies and wavefunctions of the graphene nanostructures. We apply this method describing the electronic states of the nanographenes by means of exact diagonalization of the </span>Hubbard model within a restricted Active Space. This permits us to provide a proper quantum description of the emergence of local moments in graphene and its interplay with transport. We discuss the results of this theory in the case of diradical nanographenes, such as triangulene, rectangular ribbons and the Clar’s goblet, that have been recently studied experimentally by means of STM spectroscopy. This approach permits us to calculate both the </span><span><math><mrow><mi>dI</mi><mo>/</mo><mi>dV</mi></mrow></math></span> spectra, that yields excitation energies, as well as the atomically resolved conductivity maps, that provide information on the wavefunctions of the collective spin modes.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"95 4","pages":"Article 100595"},"PeriodicalIF":6.4,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2020.100595","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2620913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Madjid Sarvghad, Theodore A. Steinberg, Geoffrey Will
{"title":"Scanning Kelvin Probe Force Microscopy as a means for comparative quantification of cold-rolling and visualizing the surface susceptibility to galvanic cells; compared to neutron diffraction and EBSD","authors":"Madjid Sarvghad, Theodore A. Steinberg, Geoffrey Will","doi":"10.1016/j.progsurf.2020.100594","DOIUrl":"https://doi.org/10.1016/j.progsurf.2020.100594","url":null,"abstract":"<div><p>High-Resolution Neutron Diffraction (HRND), Electron Back-Scatter Diffraction (EBSD) and Scanning Kelvin Probe Force Microscopy (SKPFM) techniques were used to comparatively characterize the surface electrical properties of Inconel 690 and stainless steel 316L alloys in cold-rolled and unrolled (annealed) conditions. Results indicated that a direct relation exists between the density of lattice defects (measured by HRND and EBSD) and heterogeneity of surface potential (measured by SKPFM). Mapping of the Volta potential and deconvolution of the corresponding histogram plots of the acquired data were utilized to visualize and comparatively quantify crystal lattice defects and estimate the surface susceptibility to the formation of micro/nano-galvanic cells. SKPFM was found as a reliable alternative to electron and neutron scattering techniques for comparative evaluation of energy states on alloys’ surfaces.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"95 3","pages":"Article 100594"},"PeriodicalIF":6.4,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2020.100594","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2067671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chuanlin Li , Peng Yu , Yongjun Huang , Qiang Zhou , Jiang Wu , Zhe Li , Xin Tong , Qiye Wen , Hao-Chung Kuo , Zhiming M. Wang
{"title":"Dielectric metasurfaces: From wavefront shaping to quantum platforms","authors":"Chuanlin Li , Peng Yu , Yongjun Huang , Qiang Zhou , Jiang Wu , Zhe Li , Xin Tong , Qiye Wen , Hao-Chung Kuo , Zhiming M. Wang","doi":"10.1016/j.progsurf.2020.100584","DOIUrl":"https://doi.org/10.1016/j.progsurf.2020.100584","url":null,"abstract":"<div><p><span>Metasurfaces<span> are nanopatterned structures of sub-wavelength thickness. Their effective refractive index<span> and spectral characteristic can be tailored by material composition, intrinsic and extrinsic resonances, structure size, and ambient conditions. Consequently, they allow for phase, amplitude, polarisation, and spatial control of an optical field beyond what natural materials can offer. Dielectric metasurfaces with lower loss have opened a wide range of new applications such as enhanced imaging, structural colour, </span></span></span>holography<span><span><span>, and planar sensors. In particular, beam steering and control measures such as nonlinear </span>optics, ultrafast optics, and </span>quantum optics are of increasing importance for quantum communication, computation, and information processing. In this review, the recent progress on dielectric metasurfaces is summarised, including advanced fabrication technologies and novel applications from advanced wavefront shaping to quantum platforms. In addition, a perspective for the future development of the field is presented.</span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"95 2","pages":"Article 100584"},"PeriodicalIF":6.4,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2020.100584","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3390894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cheng-Tien Chiang , Andreas Trützschler , Michael Huth , Robin Kamrla , Frank O. Schumann , Wolf Widdra
{"title":"Laser-based double photoemission spectroscopy at surfaces","authors":"Cheng-Tien Chiang , Andreas Trützschler , Michael Huth , Robin Kamrla , Frank O. Schumann , Wolf Widdra","doi":"10.1016/j.progsurf.2020.100572","DOIUrl":"https://doi.org/10.1016/j.progsurf.2020.100572","url":null,"abstract":"<div><p><span>The recent development of double photoemission<span> (DPE) spectroscopy at surfaces using laser-based high-order harmonic generation in combination with time-of-flight electron spectroscopy<span> is reviewed. Relevant experimental conditions including the solid angle for collecting photoelectron pairs, the energy and angular resolutions, as well as the repetition rate and the photon energy range of light sources are introduced. As examples, we provide an overview of laser-based DPE results on the </span></span></span>noble metals<span> Ag and Cu as well as transition metal oxides NiO and CoO. The DPE energy and angular distributions of photoelectron pairs are compared with emphasis on the possible indications of electron-electron interaction. Potential further developments including femtosecond time-resolved DPE experiments are outlined.</span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"95 1","pages":"Article 100572"},"PeriodicalIF":6.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2020.100572","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2415674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guirong Su , Sha Yang , Yingda Jiang, Jingtai Li, Shuang Li, Ji-Chang Ren, Wei Liu
{"title":"Modeling chemical reactions on surfaces: The roles of chemical bonding and van der Waals interactions","authors":"Guirong Su , Sha Yang , Yingda Jiang, Jingtai Li, Shuang Li, Ji-Chang Ren, Wei Liu","doi":"10.1016/j.progsurf.2019.100561","DOIUrl":"https://doi.org/10.1016/j.progsurf.2019.100561","url":null,"abstract":"<div><p><span><span>Chemical reactions on surfaces play central roles in heterogeneous catalysis, and most reactions involve the formation and/or the cleavage of bonds. At present, </span>density functional theory (DFT) has become the workhorse for computational investigation of reaction mechanisms, but its predictive power has been severely limited by the lack of appropriate exchange-correlation functionals. Here, we show that there are many cases where the chemical bonding and van der Waals (vdW) interactions both play a key role in chemical reactions on surfaces. After briefly introducing some DFT methods and basic theory in chemical reactions, we first demonstrate that DFT can help to understand the mechanisms of “classic” reactions that mainly dominated by covalent bonding and vdW forces, as exemplified in electrocatalytic reduction of CO</span><sub>2</sub><span> and the fabrication of 2D materials<span><span><span> on metal substrates. We next show that DFT calculations can help to uncover the tautomerization reactions<span> of molecules on metal surfaces, wherein the </span></span>hydrogen bonding and vdW forces would largely affect the reaction process. More importantly, we show that in some cases, the vdW interactions can become the decisive effect that determines the adsorption configuration, energy hierarchy, and the potential-energy surface of chemical reactions, yielding distinct pathways and products. Additionally, we highlight the importance of more realistic conditions, such as </span>surface defects, finite coverage, and temperature effects, in accurate modeling of chemical reactions. Finally, we summarize some challenges in modeling catalysis, which include many-body dispersive correction, strong correlation effect, and non-adiabatic approximations.</span></span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"94 4","pages":"Article 100561"},"PeriodicalIF":6.4,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2019.100561","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3390896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tero T. Heikkilä , Mikhail Silaev , Pauli Virtanen , F. Sebastian Bergeret
{"title":"Thermal, electric and spin transport in superconductor/ferromagnetic-insulator structures","authors":"Tero T. Heikkilä , Mikhail Silaev , Pauli Virtanen , F. Sebastian Bergeret","doi":"10.1016/j.progsurf.2019.100540","DOIUrl":"https://doi.org/10.1016/j.progsurf.2019.100540","url":null,"abstract":"<div><p><span><span><span>A ferromagnetic insulator (FI) attached to a conventional </span>superconductor (S) changes drastically the properties of the latter. Specifically, the exchange field at the FI/S interface leads to a splitting of the superconducting </span>density of states. If S is a </span>superconducting film<span><span><span>, thinner than the superconducting coherence length, the modification of the density of states occurs over the whole sample. The coexistence of the exchange splitting and superconducting correlations in S/FI structures leads to striking transport phenomena that are of interest for applications in thermoelectricity, superconducting </span>spintronics and radiation sensors. Here we review the most recent progress in understanding the transport properties of FI/S structures by presenting a complete theoretical framework based on the quasiclassical </span>kinetic equations. We discuss the coupling between the electronic degrees of freedom, charge, spin and energy, under non-equilibrium conditions and its manifestation in thermoelectricity and spin-dependent transport.</span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"94 3","pages":"Article 100540"},"PeriodicalIF":6.4,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2019.100540","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2620915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Breanna M. Wong , Greg Collinge , Alyssa J.R. Hensley , Yong Wang , Jean-Sabin McEwen
{"title":"Benchmarking the accuracy of coverage-dependent models: adsorption and desorption of benzene on Pt (1 1 1) and Pt3Sn (1 1 1) from first principles","authors":"Breanna M. Wong , Greg Collinge , Alyssa J.R. Hensley , Yong Wang , Jean-Sabin McEwen","doi":"10.1016/j.progsurf.2019.04.001","DOIUrl":"https://doi.org/10.1016/j.progsurf.2019.04.001","url":null,"abstract":"<div><p><span><span>Bimetallic catalysts have demonstrated properties favorable for upgrading biofuel through catalytic </span>hydrodeoxygenation. However, the design and optimization of such bimetallic catalysts requires the ability to construct accurate, predictive models of these systems. To generate a model that predicts the kinetic behavior of benzene adsorbed on Pt (1 1 1) and a Pt</span><sub>3</sub>Sn (1 1 1) surface alloy (Pt<sub>3</sub><span>Sn (1 1 1)), the adsorption of benzene was studied for a wide range of benzene coverages on both surfaces using density functional theory<span> (DFT) calculations. The adsorption energy of benzene was found to correlate linearly with benzene coverage on Pt (1 1 1) and Pt</span></span><sub>3</sub>Sn (1 1 1); both surfaces exhibited net repulsive lateral interactions. Through an analysis of the <em>d</em><span>-band properties of the metal surface<span>, it was determined that the coverage dependence is a consequence of the electronic interactions between benzene and the surface. The linear coverage dependence of the adsorption energy allowed us to quantify the influence of the lateral interactions on the heat of adsorption and temperature programmed desorption (TPD) spectra using a mean-field model. A comparison of our simulated TPD to experiment showed that this mean-field model adequately reproduces the desorption behavior of benzene on Pt (1 1 1) and Pt</span></span><sub>3</sub>Sn (1 1 1). In particular, the TPD correctly exhibits a broadening desorption peak as the initial coverage of benzene increases on Pt (1 1 1) and a low temperature desorption peak on Pt<sub>3</sub>Sn (1 1 1). However, due to the sensitivity of the TPD peak temperature to the desorption energy, precise alignment of experimental and theoretical TPD spectra demands an accurate calculation of the adsorption energy. Therefore, an analysis of the effect of the exchange-correlation functional on TPD modeling is presented. Through this work, we show the necessity of incorporating lateral interactions into theoretical models in order to correctly predict experimental behavior.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"94 2","pages":"Article 100538"},"PeriodicalIF":6.4,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2019.04.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3390898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jing-Tao Lü , Bing-Zhong Hu , Per Hedegård , Mads Brandbyge
{"title":"Semi-classical generalized Langevin equation for equilibrium and nonequilibrium molecular dynamics simulation","authors":"Jing-Tao Lü , Bing-Zhong Hu , Per Hedegård , Mads Brandbyge","doi":"10.1016/j.progsurf.2018.07.002","DOIUrl":"https://doi.org/10.1016/j.progsurf.2018.07.002","url":null,"abstract":"<div><p><span>Molecular dynamics (MD) simulation based on Langevin equation has been widely used in the study of structural, </span>thermal properties<span> of matter in different phases. Normally, the atomic dynamics are described by classical equations of motion<span><span> and the effect of the environment is taken into account through the fluctuating and frictional forces. Generally, the nuclear quantum effects and their coupling to other degrees of freedom are difficult to include in an efficient way. This could be a serious limitation on its application to the study of dynamical properties of materials made from light elements, in the presence of external driving electrical or thermal fields. One example of such system is single molecule dynamics on </span>metal surface, an important system that has received intense study in surface science. In this review, we summarize recent effort in extending the Langevin MD to include nuclear quantum effect and their coupling to flowing electrical current. We discuss its applications in the study of adsorbate dynamics on metal surface, current-induced dynamics in molecular junctions, and quantum thermal transport between different reservoirs.</span></span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"94 1","pages":"Pages 21-40"},"PeriodicalIF":6.4,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2018.07.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2415676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Daukiya, M.N. Nair, M. Cranney, F. Vonau, S. Hajjar-Garreau, D. Aubel, L. Simon
{"title":"Functionalization of 2D materials by intercalation","authors":"L. Daukiya, M.N. Nair, M. Cranney, F. Vonau, S. Hajjar-Garreau, D. Aubel, L. Simon","doi":"10.1016/j.progsurf.2018.07.001","DOIUrl":"https://doi.org/10.1016/j.progsurf.2018.07.001","url":null,"abstract":"<div><p><span><span><span>Since the discovery of graphene many studies focused on its functionalization by different methods. These strategies aim to find new pathways to overcome the main drawback of graphene, a missing band-gap, which strongly reduces its potential applications, particularly in the domain of nanoelectronics, despite its huge and unequaled charge carrier mobility. The necessity to contact this material with a metal has motivated a lot of studies of metal/graphene interactions and has led to the discovery of the intercalation process very early in the history of graphene. Intercalation, where the deposited atoms do not stay at the graphene surface but intercalate between the top layer and the substrate, may happen at </span>room temperature<span><span> or be induced by annealing, depending of the chemical nature of the metal. This kind of mechanism was already well-known in the earlier Graphite Intercalation Compounds<span><span> (GICs), particularly famous for one current application, the Lithium-ion Battery, which is simply an application based on the intercalation of Lithium atoms between two sheets of graphene in a graphite anode. Among numerous discoveries the GICs community also found a way to obtain graphite with superconducting properties by using intercalated </span>alkali metals. Graphene is now a playground to “revisit” and understand all these mechanisms and to discover possible new properties of graphene induced by intercalation. For example, the intercalation process may be used to decouple the graphene layer from its substrate, to change its doping level or even, in a more general way, to modify its </span></span>electronic band structure<span> and the nature of its Dirac fermions<span>. In this paper we will focus on the functionalization of graphene by using intercalation of metal atoms but also of molecules. We will give an overview of the induced modifications of the electronic band structure possibly leading to spin-orbit coupling, superconductivity, …We will see how this concept of functionalization is also now used in the framework of other </span></span></span></span>2D materials beyond graphene and of </span>van der Waals heterostructures based on these materials.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"94 1","pages":"Pages 1-20"},"PeriodicalIF":6.4,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2018.07.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2620919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}