Progress in Surface Science最新文献

{"title":"Ultrafast charge carrier and exciton dynamics in an excitonic insulator probed by time-resolved photoemission spectroscopy","authors":"Selene Mor ,&nbsp;Marc Herzog ,&nbsp;Claude Monney ,&nbsp;Julia Stähler","doi":"10.1016/j.progsurf.2022.100679","DOIUrl":"https://doi.org/10.1016/j.progsurf.2022.100679","url":null,"abstract":"<div><p>An excitonic insulator phase is expected to arise from the spontaneous formation of electron–hole pairs (excitons) in semiconductors where the exciton binding energy exceeds the size of the electronic band gap. At low temperature, these ground state excitons stabilize a new phase by condensing at lower energy than the electrons at the valence band top, thereby widening the electronic band gap. The envisioned opportunity to explore many-boson phenomena in an excitonic insulator system is triggering a very active debate on how ground state excitons can be experimentally evidenced. Here, we employ a nonequilibrium approach to spectrally disentangle the photoinduced dynamics of an exciton condensate from the entwined signature of the valence band electrons. By means of time- and angle-resolved photoemission spectroscopy of the occupied and unoccupied electronic states, we follow the complementary dynamics of conduction and valence band electrons in the photoexcited low-temperature phase of Ta₂NiSe₅, the hitherto most promising single-crystal candidate to undergo a semiconductor-to-excitonic-insulator phase transition. The photoexcited conduction electrons are found to relax within less than 1 ps. Their relaxation time is inversely proportional to their excess energy, a dependence that we attribute to the reduced screening of Coulomb interaction and the low dimensionality of Ta₂NiSe₅. Long after (<span><math><mrow><mo>&gt;</mo></mrow></math></span> 10 ps) the conduction band has emptied, the photoemission intensity below the Fermi energy has not fully recovered the equilibrium value. Notably, this seeming carrier imbalance cannot be rationalized simply by the relaxation of photoexcited electrons and holes across the semiconductor band gap. Rather, a rate equation model involving different photoemission crosssections of the valence electrons and the condensed excitons is able to reproduce the delayed recovery of the photoemission intensity below the Fermi energy. The model shows that electron quantum tunnelling between the exciton condensate and the valence band top is enabled by an extremely small activation energy of <span><math><mrow><mn>4</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>-</mo><mn>6</mn></mrow></msup></mrow></math></span> eV and explains the retarded recovery of the exciton condensate. Our findings not only determine the energy gain of ground state exciton formation with exceptional energy resolution, but also demonstrate the use of time-resolved photoemission to unveil the re-formation dynamics of an exciton condensate with femtosecond time resolution.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 4","pages":"Article 100679"},"PeriodicalIF":6.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1515357","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}

{"title":"Properties and challenges of hot-phonon physics in metals: MgB2 and other compounds","authors":"Emmanuele Cappelluti ,&nbsp;Fabio Caruso ,&nbsp;Dino Novko","doi":"10.1016/j.progsurf.2022.100664","DOIUrl":"https://doi.org/10.1016/j.progsurf.2022.100664","url":null,"abstract":"<div><p>The ultrafast dynamics of electrons and collective modes in systems out of equilibrium is crucially governed by the energy transfer from electronic degrees of freedom, where the energy of the pump source is usually absorbed, to lattice degrees of freedom. In conventional metals such process leads to an overall heating of the lattice, usually described by an effective lattice temperature <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>ph</mi></mrow></msub></mrow></math></span>, until final equilibrium with all the degrees of freedom is reached. In specific materials, however, few lattice modes provide a preferential channel for the energy transfer, leading to a non-thermal distribution of vibrations and to the onset of <span><em>hot </em><em>phonons</em></span><span>, i.e., lattice modes with a much higher population than the other modes. Hot phonons are usually encountered in semiconductors or semimetal<span> compounds, like graphene, where the preferential channel towards hot modes is dictated by the reduced electronic phase space. Following a different path, the possibility of obtaining hot-phonon physics also in metals has been also recently prompted in literature, as a result of a strong anisotropy of the electron–phonon (el-ph) coupling. In the present paper, taking MgB</span></span>₂ as a representative example, we review the physical conditions that allow a hot-phonon scenario in metals with anisotropic el-ph coupling, and we discuss the observable fingerprints of hot phonons. Novel perspectives towards the prediction and experimental observation of hot phonons in other metallic compounds are also discussed.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 3","pages":"Article 100664"},"PeriodicalIF":6.4,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1633507","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}

{"title":"Interface and defects engineering for multilayer laser coatings","authors":"Siyu Dong ,&nbsp;Hongfei Jiao ,&nbsp;Zhanshan Wang ,&nbsp;Jinlong Zhang ,&nbsp;Xinbin Cheng","doi":"10.1016/j.progsurf.2022.100663","DOIUrl":"https://doi.org/10.1016/j.progsurf.2022.100663","url":null,"abstract":"<div><p>High-reflective multilayer laser coatings are widely used in advanced optical systems from high power laser<span> facilities to high precision metrology systems. However, the real interface quality and defects will significantly affect absorption/scattering losses and laser induced damage thresholds of multilayer coatings. With the recent advances in the control of coating design and deposition processes<span><span>, these coating properties can be significantly improved when properly engineered the interface and defects. This paper reviews the recent progress in the physics of laser damage, </span>optical losses and environmental stability involved in multilayer reflective coatings for high power nanosecond near-infrared lasers. We first provide an overview of the layer growth mechanisms, ways to control the microstructures and reduce layer roughness, as well as the nature of defects which are critical to the optical loss and laser induced damage. Then an overview of interface engineering based on the design of coating structure and the regulation of deposition materials reveals their ability to improve the laser induced damage threshold, reduce the backscattering, and realize the desirable properties of environmental stability and exceptional multifunctionality. Moreover, we describe the recent progress in the laser damage and scattering mechanism of nodule defects and give the approaches to suppress the defect-induced damage and scattering of the multilayer laser coatings. Finally, the present challenges and limitations of high-performance multilayer laser coatings are highlighted, along with the comments on likely trends in future.</span></span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 3","pages":"Article 100663"},"PeriodicalIF":6.4,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1884295","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}

{"title":"Spin-polarized electrons in atomic layer materials formed on solid surfaces","authors":"Kazuyuki Sakamoto ,&nbsp;Takahiro Kobayashi ,&nbsp;Koichiro Yaji ,&nbsp;Tatsuya Shishidou ,&nbsp;Markus Donath","doi":"10.1016/j.progsurf.2022.100665","DOIUrl":"https://doi.org/10.1016/j.progsurf.2022.100665","url":null,"abstract":"<div><p><span>In this review, we summarize the recent progress in the understanding of the spin-polarized electronic states in two-dimensional (2D) atomic layer materials (ALMs) formed on solid surfaces. The spin-polarized electronic states caused by the combination of spin-orbit coupling (SOC) with broken spatial inversion symmetry along the surface normal direction is one of the most exotic phenomena that appears on ALMs formed on solid surfaces as well as clean solid surfaces. The so-called Rashba-Bychkov (RB) effect that arises from the potential gradient induced by broken inversion symmetry was believed to be the main origin of these spin-polarized electronic states. However, the spin texture of most ALMs are different from that caused by the ideal RB effect. Due to the high impact of the spin-polarized electronic states of </span>2D materials<span><span><span> in not only spin-related fundamental science but also in applications since they are the key concepts to realize future semiconductor spintronics devices, much efforts have been made to elucidate the origin of these peculiar spin textures. So far, the deviations in spin texture from the ideal one have been attributed to be induced by perturbation, such as entanglement of spin and orbital momenta. In this review, we first illustrate how the symmetry of the ALM’s atomic structure can affect the spin texture, and then introduce that various spin textures, ranging from the RB-type and symmetry-induced type to spin textures that cannot be explained based on the origins proposed so far, can be simply induced by the orbital </span>angular momentum<span>. This review aims to provide an overview on the insights gained on the spin-polarized electronic states of ALMs and to point out opportunities for exploring exotic physical properties when combining spin and other physics<span>, e.g. superconductivity, and to realize future spintronics-based </span></span></span>quantum devices.</span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 3","pages":"Article 100665"},"PeriodicalIF":6.4,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1633509","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}

{"title":"Atomically resolved interlayer electronic states in complex oxides by using cross-sectional scanning tunneling microscopy","authors":"Bo-Chao Huang ,&nbsp;Chun-Chih Hsu ,&nbsp;Ying-Hao Chu ,&nbsp;Ya-Ping Chiu","doi":"10.1016/j.progsurf.2022.100662","DOIUrl":"https://doi.org/10.1016/j.progsurf.2022.100662","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Complex oxides show a rich variety of functionalities through their strong coupling to the lattice, electron, orbital, and spin degrees of freedom not only at oxide heterointerfaces but also in layered cuprates. For the topic of oxide heterointerfaces, with advances in growth, delicate tuning of the atomic termination at the interface with layer-by-layer precision is now achievable. The improvements in growth open up opportunities to manipulate the coupling of 3&lt;em&gt;d&lt;/em&gt; &lt;!--&gt;electrons at complex oxide interfaces, creating intriguing phenomena that are not attainable in bulk constituents alone. For example, two-dimensional electron gases have been found at LaAlO&lt;sub&gt;3&lt;/sub&gt;/SrTiO&lt;sub&gt;3&lt;/sub&gt; heterointerfaces.&lt;/p&gt;&lt;p&gt;For the topic of high-temperature layered cuprates (for example, YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;6+x&lt;/sub&gt; (YBCO&lt;sub&gt;6+x&lt;/sub&gt;)), charge order (CO) has been the key to understanding the full picture for high transition temperature superconductors. However, two central questions that involve the general picture of the stacking pattern for the CO interlayer in YBCO&lt;sub&gt;6+&lt;/sub&gt;&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; and how exactly the CuO chain influences the CO on the CuO&lt;sub&gt;2&lt;/sub&gt; plane remain an open issue. Investigating the nanostructure of the CO and its spatial interplay with superconductivity, as well as the relation between CuO&lt;sub&gt;2&lt;/sub&gt; bilayers and CuO chain layers simultaneously with atomic-scale spatial and energy resolution, is still under debate. Disentangling the physical origins of the interface properties and interlayer electronic states in complex oxides requires an experimentally direct probe localized at the interfaces and characterization of atomically resolved electronic states in oxides.&lt;/p&gt;&lt;p&gt;In this paper, we review the utilization of cross-sectional scanning tunneling microscopy (XSTM) and spectroscopy (XSTS) to directly probe electronic states with atomic precision right at and across complex oxide interfaces and interlayers. With this technique, we probe the structural and electronic properties in complex oxides, revealing the underlying detailed electronic structure (e.g., local electronic density of states and ferroelectric polarization in oxide interfaces, as well as the spatial configuration of CO and its interplay with the superconductivity in YBCO&lt;sub&gt;6+x&lt;/sub&gt;). This forms the basis for an atomic-scale physical understanding of complex oxides, which is also central for designing complex oxide devices.&lt;/p&gt;&lt;p&gt;In this review article, the first part gives a brief design idea of the XSTM measurement, a brief description of the cleavage technique, and spectroscopic analysis of XSTM measurements. The second part addresses several models for termination engineering of the electronic states across complex oxide interfaces by using XSTM measurements. The topics to be discussed include the local electronic structure across LaAlO&lt;sub&gt;3&lt;/sub&gt;/SrTiO&lt;sub&gt;3&lt;/sub&gt;, and ferroelectric polarization-modulated band bending at","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 2","pages":"Article 100662"},"PeriodicalIF":6.4,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1515360","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}

{"title":"Multifunctional cold spray coatings for biological and biomedical applications: A review","authors":"Tzu-Ying Liao ,&nbsp;Arne Biesiekierski ,&nbsp;Christopher C. Berndt ,&nbsp;Peter C. King ,&nbsp;Elena P. Ivanova ,&nbsp;Helmut Thissen ,&nbsp;Peter Kingshott","doi":"10.1016/j.progsurf.2022.100654","DOIUrl":"https://doi.org/10.1016/j.progsurf.2022.100654","url":null,"abstract":"<div><p>A variety of coating techniques are available for medical devices to be tailored with surface properties aimed at optimizing their performance in biological environments. Cold spray, as a member of the thermal spray family, is now being exploited to efficiently deposit micro- to nanometer sized metallic or non-metallic particles on surgical implants, medical devices and surfaces in the healthcare environment to create functional coatings. Cold spray has attracted attention in the context of biomedical applications due to the fact that multiple materials can be combined easily at the surface of these devices, and that oxygen-sensitive and heat-sensitive organic molecules, including bioactive compounds, can be incorporated in these coatings due to the relatively low temperatures used in the process. The ability to maintain material and chemical properties and the ability to create functional coatings make the cold spray process particularly suitable for applications in the MedTech industry sector.</p><p>This review explores the fabrication of cold spray coatings including the types of materials that have been used for biomedical purposes, provides a detailed analysis of the factors affecting cold spray coating performance, and gives an overview over the most recent developments related to the technology. Cold spray coatings that have been used until this point in time in biomedical applications can be broadly classified as biocompatible coatings, anti-infective coatings, anti-corrosive coatings, and wear-resistant coatings. In addition, this review discusses how these applications can be broadened, for example by providing antiviral effect against coronavirus (COVID-19). While we highlight examples for multifunctional cold spray coatings, we also explore the current challenges and opportunities for cold spray coatings in the biomedical field and predict likely future developments.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 2","pages":"Article 100654"},"PeriodicalIF":6.4,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2621390","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}

{"title":"Effective Work Functions of the Elements","authors":"Hiroyuki Kawano","doi":"10.1016/j.progsurf.2020.100583","DOIUrl":"https://doi.org/10.1016/j.progsurf.2020.100583","url":null,"abstract":"&lt;div&gt;&lt;p&gt;As a much-enriched supplement to the previous review paper entitled the “Effective work functions for ionic and electronic emissions from mono- and polycrystalline surfaces” [Prog. Surf. Sci. 83 (2008) 1–165], the present monograph summarizes a comprehensive and up-to-date database in Table 1, which includes more than ten thousands of experimental and theoretical data accumulated mainly during the last half century on the work functions (&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) effective for positive-ionic, electronic and negative-ionic emissions from mono- and polycrystalline surfaces of 88 kinds of chemical elements (&lt;sub&gt;1&lt;/sub&gt;H–&lt;sub&gt;99&lt;/sub&gt;Es), and also which includes the main experimental condition and method employed for each sample specimen (bulk or film) together with 490 footnotes. From the above database originating from 4461 references published to date in the fields of both physics and chemistry, the most probable values of &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; for substantially clean surfaces are statistically estimated for about 600 surface species of mono- and polycrystals. The values recommended for &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; together with &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; in Table 2 are much more abundant in both surface species and data amount, and also they may be more reliable and convenient than those in popular handbooks and reviews consulted widely still today by great many workers, because the latter is based on less-plentiful data on &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; published generally before &lt;span&gt;&lt;math&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;1980 and also because it covers no value recommended for &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;. Consequently, Table 1 may be more advantageous as the latest and most abundant database on work functions (especially &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) for quickly referring to a variety of data obtained under specified conditions. Comparison of the most probable values of &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; recommended for each surface species between this article and ","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"97 1","pages":"Article 100583"},"PeriodicalIF":6.4,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3078165","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}

{"title":"Obituary for Sydney Davison: The founder of progress in surface science","authors":"Prue Davison ,&nbsp;Aart Kleyn ,&nbsp;Hrvoje Petek","doi":"10.1016/j.progsurf.2021.100647","DOIUrl":"https://doi.org/10.1016/j.progsurf.2021.100647","url":null,"abstract":"","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"96 4","pages":"Article 100647"},"PeriodicalIF":6.4,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1784755","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}

{"title":"Beyond graphene: Clean, hydrogenated and halogenated silicene, germanene, stanene, and plumbene","authors":"Friedhelm Bechstedt ,&nbsp;Paola Gori ,&nbsp;Olivia Pulci","doi":"10.1016/j.progsurf.2021.100615","DOIUrl":"https://doi.org/10.1016/j.progsurf.2021.100615","url":null,"abstract":"<div><p><span><span>The fascinating electronic and optoelectronic properties of freestanding graphene and the possible inclusion of novel two-dimensional (2D) systems in silicon-based electronics have driven the search for atomic layers consisting of other group-IV elements Si, </span>Ge, Sn, and Pb, which form similar hexagonal lattices and are isoelectronic to graphene. The resulting 2D crystals </span>silicene<span><span>, germanene, stanene and plumbene, referred as Xenes, but also their functionalized counterparts, e.g. the hydrogenated sheet crystals, named as Xanes, silicane, germanane, and stanane, are in the focus of this review article. In addition, halogenated Xenes are investigated. The consequences of the larger atomic radii on the atomic geometry, the </span>energetic stability, and possible epitaxial preparations are discussed.</span></p><p><span>In the case of honeycomb atomic arrangements, the low-energy electronic excitations<span><span> are ruled by almost linear bands. Spin–orbit coupling opens small gaps leading to Dirac fermions with finite effective masses. The linear bands give rise to an absorbance of the Xenes determined by the finestructure constant in the long-wavelength regime. While for vanishing photon energies the excitonic influence is still an open question, saddle-point </span>excitons and excitons at </span></span><span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span><span><span> van Hove singularities appear at higher frequencies. After opening substantial fundamental gaps by hydrogenation, the absorption edges of the Xanes, silicane, germanane, and stanane, are dominated by bound excitons with extremely large binding energies. Other chemical functionalizations, but also vertical electric fields, yield electronic structures ranging from topological to trivial insulators. Even a quantum spin Hall phase is predicted at </span>room temperature. The topological character and the possible quantization of the spin Hall conductivity are studied versus gap inversion, chemical functionalization, and Rashba spin–orbit interaction. The drastic changes of the electronic properties of Xenes with chemical functionalization, interaction with the substrate, and external perturbations, open future opportunities for tailoring fundamental properties and, therefore, interesting applications in novel electronic and optoelectronic nanodevices.</span></p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"96 3","pages":"Article 100615"},"PeriodicalIF":6.4,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2021.100615","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2139618","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}

{"title":"Advances in two-dimensional heterostructures by mono-element intercalation underneath epitaxial graphene","authors":"Songhao Wu ,&nbsp;Quanzhen Zhang ,&nbsp;Huixia Yang ,&nbsp;Yuanxiao Ma ,&nbsp;Teng Zhang ,&nbsp;Liwei Liu ,&nbsp;Hong-Jun Gao ,&nbsp;Yeliang Wang","doi":"10.1016/j.progsurf.2021.100637","DOIUrl":"https://doi.org/10.1016/j.progsurf.2021.100637","url":null,"abstract":"<div><p><span><span><span>Two-dimensional (2D) materials have displayed many remarkable physical properties, including 2D superconductivity, magnetism, and layer-dependent bandgaps. However, it is difficult for a single 2D material to meet complex practical requirements. Heterostructures obtained by vertically stacking different kinds of 2D materials have extensively attracted researchers’ attention because of their rich electronic features. With heterostructures, the constraints of lattice matching can be overcome. Meanwhile, high application potential has been explored for electronic and </span>optoelectronic devices, including tunneling transistors, flexible electronics, and </span>photodetectors. Specifically, graphene-based </span>van der Waals heterostructures (vdWHs) by intercalation are emerging to realize various functional heterostructures-based electronic devices. Intercalating atoms under epitaxial graphene can efficiently decouple graphene from the substrate, and is expected to realize rich novel electronic properties in graphene. In this study, we systematically review the progress of the mono-element intercalation in graphene-based vdWHs, including the intercalation mechanism, intercalation-modified electronic properties, and the practical applications of 2D intercalated heterostructures. This work would inspire edge-cutting ideas in the scientific frontiers of 2D materials.</p></div>","PeriodicalId":416,"journal":{"name":"Progress in Surface Science","volume":"96 3","pages":"Article 100637"},"PeriodicalIF":6.4,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.progsurf.2021.100637","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1994639","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}