| 1. |
|
|
| 2. |
- Hibar, D. P., et al.
(author)
-
Cortical abnormalities in bipolar disorder: An MRI analysis of 6503 individuals from the ENIGMA Bipolar Disorder Working Group
- 2018
-
In: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 23:4, s. 932-942
-
Journal article (peer-reviewed)abstract
- Despite decades of research, the pathophysiology of bipolar disorder (BD) is still not well understood. Structural brain differences have been associated with BD, but results from neuroimaging studies have been inconsistent. To address this, we performed the largest study to date of cortical gray matter thickness and surface area measures from brain magnetic resonance imaging scans of 6503 individuals including 1837 unrelated adults with BD and 2582 unrelated healthy controls for group differences while also examining the effects of commonly prescribed medications, age of illness onset, history of psychosis, mood state, age and sex differences on cortical regions. In BD, cortical gray matter was thinner in frontal, temporal and parietal regions of both brain hemispheres. BD had the strongest effects on left pars opercularis (Cohen's d='0.293; P=1.71 × 10 '21), left fusiform gyrus (d='0.288; P=8.25 × 10 '21) and left rostral middle frontal cortex (d='0.276; P=2.99 × 10 '19). Longer duration of illness (after accounting for age at the time of scanning) was associated with reduced cortical thickness in frontal, medial parietal and occipital regions. We found that several commonly prescribed medications, including lithium, antiepileptic and antipsychotic treatment showed significant associations with cortical thickness and surface area, even after accounting for patients who received multiple medications. We found evidence of reduced cortical surface area associated with a history of psychosis but no associations with mood state at the time of scanning. Our analysis revealed previously undetected associations and provides an extensive analysis of potential confounding variables in neuroimaging studies of BD. © 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
|
|
| 3. |
- Santangelo, James S., et al.
(author)
-
Global urban environmental change drives adaptation in white clover
- 2022
-
In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 375
-
Journal article (peer-reviewed)abstract
- Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural dines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.
|
|
| 4. |
- Coletti, C., et al.
(author)
-
Surface studies of hydrogen etched 3C-SiC(001) on Si(001)
- 2007
-
In: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 91:6, s. 061914-
-
Journal article (peer-reviewed)abstract
- Themorphology and structure of 3C-SiC(001) surfaces, grown on Si(001) andprepared via hydrogen etching, are studied using atomic force microscopy(AFM), low-energy electron diffraction (LEED), and Auger electron spectroscopy (AES).On the etched samples, flat surfaces with large terraces andatomic steps are revealed by AFM. In ultrahigh vacuum asharp LEED pattern with an approximate (5×1) periodicity is observed. AES studies reveal a “bulklike” composition up to the nearsurface region and indicate that an overlayer consisting of aweakly bound silicon oxide monolayer is present.
|
|
| 5. |
- Forti, S., et al.
(author)
-
Large-area homogeneous quasifree standing epitaxial graphene on SiC(0001): Electronic and structural characterization
- 2011
-
In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 84:12
-
Journal article (peer-reviewed)abstract
- The growth of epitaxial graphene on SiC has been identified as one of the most promising techniques to produce graphene for electronic applications. In this paper, we present a systematic study of the electronic and structural properties of large-area quasifree standing epitaxial monolayer graphene grown on top of the SiC(0001) surface. For this purpose, we combine the thermal treatment of SiC in Ar atmosphere to achieve a homogeneous coverage of the surface with the hydrogen intercalation process, which leads to the removal of the interaction between the substrate and the carbon layer. The band structure in the vicinity of the (K) over bar point is measured using high-resolution angle-resolved photoelectron spectroscopy. A detailed analysis of the quasiparticle dynamics reveals a renormalization of the band velocity estimated to about 3% at energies around 200 meV below the Fermi level, which mainly originates from electron-phonon interaction. Further analysis of the momentum distribution curves leads to the formulation of a model for the doping reduction in such a system in the course of sample annealing above 650 degrees C. The uniformity and homogeneity of the graphene is demonstrated by means of low-energy electron microscopy (LEEM). Microphotoelectron spectroscopy data confirm the high structural quality and homogeneity of the quasifree standing graphene. Using LEEM and scanning tunneling microscopy, we demonstrate that the hydrogen desorption at elevated temperatures of approximately 750 degrees C sets in on the graphene terraces rather than via the step edges.
|
|
| 6. |
- Link, S., et al.
(author)
-
Introducing strong correlation effects into graphene by gadolinium intercalation
- 2019
-
In: Physical Review B. - 2469-9950. ; 100:12
-
Journal article (peer-reviewed)abstract
- Exotic ordered ground states driven by electronic correlations are expected to be induced in monolayer graphene when doped to the Van Hove singularity. Such doping levels are reached by intercalating Gd in graphene on SiC(0001), resulting in a strong homogeneity and stability. The electronic spectrum now exhibits severe renormalizations. Flat bands develop which are driven by electronic correlations according to our theoretical studies. Due to strong electron-phonon coupling in this regime, polaron replica bands develop. Thus, interesting ordered ground states should be made accessible.
|
|
| 7. |
- Nigge, P., et al.
(author)
-
Room temperature strain-induced Landau levels in graphene on a wafer-scale platform
- 2019
-
In: Science Advances. - : AMER ASSOC ADVANCEMENT SCIENCE. - 2375-2548. ; 5:11
-
Journal article (peer-reviewed)abstract
- Graphene is a powerful playground for studying a plethora of quantum phenomena. One of the remarkable properties of graphene arises when it is strained in particular geometries and the electrons behave as if they were under the influence of a magnetic field. Previously, these strain-induced pseudomagnetic fields have been explored on the nano- and micrometer-scale using scanning probe and transport measurements. Heteroepitaxial strain, in contrast, is a wafer-scale engineering method. Here, we show that pseudomagnetic fields can be generated in graphene through wafer-scale epitaxial growth. Shallow triangular nanoprisms in the SiC substrate generate strain-induced uniform fields of 41 T, enabling the observation of strain-induced Landau levels at room temperature, as detected by angle-resolved photoemission spectroscopy, and confirmed by model calculations and scanning tunneling microscopy measurements. Our work demonstrates the feasibility of exploiting strain-induced quantum phases in two-dimensional Dirac materials on a wafer-scale platform, opening the field to new applications.
|
|
| 8. |
|
|
| 9. |
- Riedl, C., et al.
(author)
-
Quasi-Free-Standing Epitaxial Graphene on SiC Obtained by Hydrogen Intercalation
- 2009
-
In: Physical Review Letters. - 1079-7114. ; 103:24
-
Journal article (peer-reviewed)abstract
- Quasi-free-standing epitaxial graphene is obtained on SiC(0001) by hydrogen intercalation. The hydrogen moves between the (6 root 3 x 6 root 3) R 30 degrees reconstructed initial carbon layer and the SiC substrate. The topmost Si atoms which for epitaxial graphene are covalently bound to this buffer layer, are now saturated by hydrogen bonds. The buffer layer is turned into a quasi-free-standing graphene monolayer with its typical linear pi bands. Similarly, epitaxial monolayer graphene turns into a decoupled bilayer. The intercalation is stable in air and can be reversed by annealing to around 900 degrees C.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Aprojanz, J., et al.
(författare)
-
High-Mobility Epitaxial Graphene on Ge/Si(100) Substrates
- 2020
-
Ingår i: ACS applied materials & interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:38, s. 43065-43072
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene was shown to reveal intriguing properties of its relativistic two-dimensional electron gas; however, its implementation to microelectronic applications is missing to date. In this work, we present a comprehensive study of epitaxial graphene on technologically relevant and in a standard CMOS process achievable Ge(100) epilayers grown on Si(100) substrates. Crystalline graphene monolayer structures were grown by means of chemical vapor deposition (CVD). Using angle-resolved photoemission spectroscopy and in situ surface transport measurements, we demonstrate their metallic character both in momentum and real space. Despite numerous crystalline imperfections, e.g., grain boundaries and strong corrugation, as compared to epitaxial graphene on SiC(0001), charge carrier mobilities of 1 × 104 cm2/Vs were obtained at room temperature, which is a result of the quasi-charge neutrality within the graphene monolayers on germanium and not dependent on the presence of an interface oxide. The interface roughness due to the facet structure of the Ge(100) epilayer, formed during the CVD growth of graphene, can be reduced via subsequent in situ annealing up to 850 °C coming along with an increase in the mobility by 30%. The formation of a Ge(100)-(2 × 1) structure demonstrates the weak interaction and effective delamination of graphene from the Ge/Si(100) substrate.
|
|
| 16. |
- Baringhaus, J., et al.
(författare)
-
Bipolar gating of epitaxial graphene by intercalation of Ge
- 2014
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 104:26
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, the ambivalent behavior of Ge intercalation is studied by means of scanning tunneling microscopy and spectroscopy as well as local 4-point probe transport measurements. In quantitative agreement with angle-resolved photoemission experiments, both p-and n-type doped graphene areas and their doping level were identified by local spectroscopy. The p-doped areas appear higher by 2 angstrom with respect to the n-doped areas suggesting incorporation of thicker Ge-layers accompanied by a modified coupling to the initial SiC-surface. Furthermore, the sheet resistance was measured on each of the patches separately. The intrinsic imbalance between the carrier types in the different areas is well reflected by the transport study. The process of intercalation does not affect the transport properties in comparison to pristine graphene pointing to a sufficient homogeneity of the decoupled graphene layer. Transport measurements across chemically gated pn-junctions reveal increased resistances, possibly due to enlarged tunneling barriers. (C) 2014 AIP Publishing LLC.
|
|
| 17. |
|
|
| 18. |
- Bohm-Starke, N, et al.
(författare)
-
Increased intraepithelial innervation in women with vulvar vestibulitis syndrome
- 1998
-
Ingår i: Gynecologic and obstetric investigation. - : S. Karger AG. - 0378-7346 .- 1423-002X. ; 46:4, s. 256-260
-
Tidskriftsartikel (refereegranskat)abstract
- Women with vulvar vestibulitis syndrome (VVS) suffer from severe pain and discomfort in the area around the introitus at almost any stimulus that causes pressure within the vestibule. In spite of the severe sensory symptoms present in these women, the influence of the peripheral nerves in the vulvar vestibulum has not been clarified before. In this study the nerve supply in the vestibular mucosa in women with VVS and in healthy women free from vulvar symptoms has been revealed by PGP 9.5 immunohistochemistry. The results show a significant increase in the number of intraepithelial nerve endings in women with VVS, indicating an alteration in the nerve supply in the afflicted area.
|
|
| 19. |
- Bohm-Starke, N, et al.
(författare)
-
Neurochemical characterization of the vestibular nerves in women with vulvar vestibulitis syndrome
- 1999
-
Ingår i: Gynecologic and obstetric investigation. - : S. Karger AG. - 0378-7346 .- 1423-002X. ; 48:4, s. 270-275
-
Tidskriftsartikel (refereegranskat)abstract
- Women with vulvar vestibulitis syndrome (VVS) have a distinct burning pain provoked by almost any stimuli in the area around the vaginal introitus. In a previous study we observed an increased number of intraepithelial free nerve endings in women with VVS. The aim of the present study was to neurochemically characterize the superficial nerves in the vulvar vestibular mucosa of women with VVS. Immunohistochemical methods were used to detect neuropeptides normally found in various types of nerve fibers. Calcitonin gene-related peptide, which is known to exist in nociceptive afferent nerves, was the only neuropeptide detected in the superficial nerves of the vestibular mucosa. These findings confirm our previous theory that the free nerve endings within the epithelium are nociceptors.
|
|
| 20. |
|
|
| 21. |
- Brauner, A, et al.
(författare)
-
Psoriasin, a novel anti-Candida albicans adhesin
- 2018
-
Ingår i: Journal of molecular medicine (Berlin, Germany). - : Springer Science and Business Media LLC. - 1432-1440 .- 0946-2716. ; 96:6, s. 537-545
-
Tidskriftsartikel (refereegranskat)
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
- Coletti, C., et al.
(författare)
-
Large area quasi-free standing monolayer graphene on 3C-SiC(111)
- 2011
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 99:8
-
Tidskriftsartikel (refereegranskat)abstract
- Large scale, homogeneous quasi-free standing monolayer graphene is obtained on cubic silicon carbide, i.e., the 3C-SiC(111) surface, which represents an appealing and cost effective platform for graphene growth. The quasi-free monolayer is produced by intercalation of hydrogen under the interfacial, (6 root 3 x 6 root 3)R30 degrees-reconstructed carbon layer. After intercalation, angle resolved photoemission spectroscopy reveals sharp linear pi-bands. The decoupling of graphene from the substrate is identified by x-ray photoemission spectroscopy and low energy electron diffraction. Atomic force microscopy and low energy electron microscopy demonstrate that homogeneous monolayer domains extend over areas of hundreds of square-micrometers. (C) 2011 American Institute of Physics. [doi:10.1063/1.3618674]
|
|
| 26. |
- Coletti, C., et al.
(författare)
-
Revealing the electronic band structure of trilayer graphene on SiC: An angle-resolved photoemission study
- 2013
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 88:15
-
Tidskriftsartikel (refereegranskat)abstract
- In recent times, trilayer graphene has attracted wide attention owing to its stacking and electric-field-dependent electronic properties. However, a direct and well-resolved experimental visualization of its band structure has not yet been reported. In this paper, we present angle-resolved photoemission spectroscopy data which show with high resolution the electronic band structure of trilayer graphene obtained on alpha-SiC(0001) and beta-SiC(111) via hydrogen intercalation. Electronic bands obtained from tight-binding calculations are fitted to the experimental data to extract the interatomic hopping parameters for Bernal and rhombohedral stacked trilayers. Low-energy electron microscopy measurements demonstrate that the trilayer domains extend over areas of tens of square micrometers, suggesting the feasibility of exploiting this material in electronic and photonic devices. Furthermore, our results suggest that, on SiC substrates, the occurrence of a rhombohedral stacked trilayer is significantly higher than in natural bulk graphite.
|
|
| 27. |
- Forti, S., et al.
(författare)
-
Mini-Dirac cones in the band structure of a copper intercalated epitaxial graphene superlattice
- 2016
-
Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 3:3
-
Tidskriftsartikel (refereegranskat)abstract
- The electronic band structure of an epitaxial graphene superlattice, generated by intercalating a monolayer of Cu atoms, is directly imaged by angle-resolved photoelectron spectroscopy. The 3.2 nm lateral period of the superlattice is induced by a varying registry between the graphene honeycomb and the Cu atoms as imposed by the heteroepitaxial interface Cu/SiC. The carbon atoms experience a lateral potential across the supercell of an estimated value of about 65 meV. The potential leads to strong energy renormalization in the band structure of the graphene layer and the emergence of mini-Dirac cones. The mini-cones' band velocity is reduced to about half of graphene's Fermi velocity. Notably, the ordering of the interfacial Cu atoms can be reversibly blocked by mild annealing. The superlattice indeed disappears at∼220 °C.
|
|
| 28. |
- Hellberg, C., et al.
(författare)
-
Evidence and evidence gaps in assessments and interventions in areas related to social work research and practice - an overview of four evidence maps
- 2023
-
Ingår i: European Journal of Social Work. - : Informa UK Limited. - 1369-1457 .- 1468-2664. ; 26:5
-
Tidskriftsartikel (refereegranskat)abstract
- This overview of four evidence maps is based on systematic reviews of assessment and interventions in social work practice. The aim was to investigate the evidence and evidence gaps within four important areas for social work research and practice. Descriptive data on search strategies and domains were collected from four evidence maps, on Social Assistance, Substance Dependence, Care for older adults respectively for persons with disabilities. The scientific quality and scientific evidence were assessed. Key findings were summarised by analyzing and discussing common and specific elements in the evidence maps. The overview was undertaken in close collaboration between researchers with expertise in the field and a government agency. The overview identified both evidence and evidence gaps with respect to effects and experiences of interventions and assessment methods in four evidence maps. Evidence maps provide a comprehensive picture of the state of social services research and can thereby be of use to both researchers and practitioners, and in the production of evidence based social work.
|
|
| 29. |
- Kotschik, Pia, et al.
(författare)
-
The upcoming European Soil Monitoring Law : An effective instrument for the protection of terrestrial ecosystems?
- 2024
-
Ingår i: Integrated Environmental Assessment and Management. - : John Wiley & Sons. - 1551-3777 .- 1551-3793. ; 20:2, s. 316-321
-
Tidskriftsartikel (refereegranskat)abstract
- Soils are a precious resource consistently placed under several threats, and urgently, in need of protection within a regulatory framework at the European level. Soils are central to the provision of environmental services as well as human existence on earth. The need to protect soil has been identified by several recent European strategies and fortunately, a specific European Regulation for soil protection is on the way - the European Soil Monitoring Law (formerly: Soil Health Law). However, efforts need to ensure that the upcoming Soil Monitoring law closes gaps between existing regulations for chemicals and acknowledges current European strategies for environmental protection and sustainability. This brief communication started from a fruitful discussion among SETAC Global Soils Interest Group members on a recent public consultation on the newly proposed Soil Monitoring Law of the European Commission and highlights critical points focusing on the chemical pollution of soils. We emphasise urgent needs such as the essential definition of a 'healthy state' of soils, the implementation of a suitable set of indicators and quality standards for the description of physical, chemical and biological states of soils, the enforcement of the 'polluters pay's' principle and the establishment of a European wide monitoring program. Results from monitoring need to be fed back into regulatory frameworks, including the regulation of chemicals. Guidance documents for the risk assessment of chemicals are outdated and need to be updated. Finally, actions need to be taken to foster healthy soils, stop biodiversity decline and ensure the functioning of ecosystem services for future generations.
|
|
| 30. |
- Riedl, C., et al.
(författare)
-
Precise in situ thickness analysis of epitaxial graphene layers on SiC(0001) using low-energy electron diffraction and angle resolved ultraviolet photoelectron spectroscopy
- 2008
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:3
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate an easy and practical method for the thickness analysis of epitaxial graphene on SiC(0001) that can be applied continuously during the preparation procedure. Fingerprints in the spot intensity spectra in low energy electron diffraction (LEED) allow for the exact determination of the number of layers for the first three graphene layers. The LEED data have been correlated with the electronic bandstructure around the (K) over bar -point of the graphene Brillouin zone as investigated by laboratory based angle resolved ultraviolet photoelectron spectroscopy using He II excitation. The morphology and homogeneity of the graphene layers can be analyzed by low energy electron microscopy. (C) 2008 American Institute of Physics.
|
|
| 31. |
- Schädlich, Philip, et al.
(författare)
-
Domain Boundary Formation Within an Intercalated Pb Monolayer Featuring Charge-Neutral Epitaxial Graphene
- 2023
-
Ingår i: Advanced Materials Interfaces. - 2196-7350. ; 10:27
-
Tidskriftsartikel (refereegranskat)abstract
- The synthesis of new graphene-based quantum materials by intercalation is an auspicious approach. However, an accompanying proximity coupling depends crucially on the structural details of the new heterostructure. It is studied in detail the Pb monolayer structure after intercalation into the graphene buffer layer on the SiC(0001) interface by means of photoelectron spectroscopy, x-ray standing waves, and scanning tunneling microscopy. A coherent fraction close to unity proves the formation of a flat Pb monolayer on the SiC surface. An interlayer distance of 3.67 Å to the suspended graphene underlines the formation of a truly van der Waals heterostructure. The 2D Pb layer reveals a quasi ten-fold periodicity due to the formation of a grain boundary network, ensuring the saturation of the Si surface bonds. Moreover, the densely-packed Pb layer also efficiently minimizes the doping influence by the SiC substrate, both from the surface dangling bonds and the SiC surface polarization, giving rise to charge-neutral monolayer graphene. The observation of a long-ranged ((Formula presented.)) reconstruction on the graphene lattice at tunneling conditions close to Fermi energy is most likely a result of a nesting condition to be perfectly fulfilled.
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
- Starke, Mikaela, 1960, et al.
(författare)
-
Parenting with disabilities: Experiences from implementing a parenting support programme in Sweden
- 2013
-
Ingår i: Journal of Intellectual Disabilities. - : SAGE Publications. - 1744-6295 .- 1744-6309. ; 17:2, s. 145-156
-
Tidskriftsartikel (refereegranskat)abstract
- This article reports on the initial stages of implementing an Australian-based education programme for parents with intellectual disabilities (IDs) in Sweden. The clinical utility of the programme, Parenting Young Children (PYC), in the new country context is explored through Swedish professionals' experiences in learning and using it. Study participants found PYC well suited for use in their working environment. Most of them reported the programme to have strengthened their work with parents. The programme was seen as benefiting both the study participants in their work with parents with IDs and these parents themselves, and its structure and content were found to be helpful in several ways. The checklists forming part of PYC were considered useful, but their purpose was sometimes misunderstood. The reported study helps to identify what is needed to improve the translation of the programme into the new country context, to promote appropriate and more effective use of programme materials. © 2013 The Author(s).
|
|
| 35. |
- Stöhr, Alexander, et al.
(författare)
-
Graphene Ribbon Growth on Structured Silicon Carbide
- 2017
-
Ingår i: Annalen der Physik. - : Wiley. - 0003-3804. ; 529:11
-
Tidskriftsartikel (refereegranskat)abstract
- Structured Silicon Carbide was proposed to be an ideal template for the production of arrays of edge specific graphene nanoribbons (GNRs), which could be used as a base material for graphene transistors. We prepared periodic arrays of nanoscaled stripe-mesas on SiC surfaces using electron beam lithography and reactive ion etching. Subsequent epitaxial graphene growth by annealing is differentiated between the basal-plane mesas and the faceting stripe walls as monitored by means of atomic force microscopy (AFM). Microscopic low energy electron diffraction (μ-LEED) revealed that the graphene ribbons on the facetted mesa side walls grow in epitaxial relation to the basal-plane graphene with an armchair orientation at the facet edges. The π-band system of the ribbons exhibits linear bands with a Dirac like shape corresponding to monolayer graphene as identified by angle-resolved photoemission spectroscopy (ARPES).
|
|
| 36. |
- van Lankveld, JJDM, et al.
(författare)
-
Women's sexual pain disorders
- 2010
-
Ingår i: The journal of sexual medicine. - : Oxford University Press (OUP). - 1743-6109 .- 1743-6095. ; 7:11 Pt 2, s. 615-631
-
Tidskriftsartikel (refereegranskat)
|
|
| 37. |
- Virojanadara, Chariya, et al.
(författare)
-
Silicon adatom chains and one-dimensionally confined electrons on 4H-SiC(1-102): The (2x1) reconstruction
- 2008
-
Ingår i: Surface Science. - : Elsevier. - 0039-6028 .- 1879-2758. ; 602:22, s. 3506-3509
-
Tidskriftsartikel (refereegranskat)abstract
- The electronic and atomic structure of the 4H-SiC surface was investigated. Photoemission data indicate that the surface contains about 2 Si layers on top of the bulk layers. Scanning tunneling microscopy images show that these adlayers are terminated by an ordered array of adatom chains separated by the unit cell size. An electronic surface state located at a binding energy of 0.8 eV shows one-dimensional confinement with dispersion only along the chains. Based on the experimental observations, a tentative (2 × 1) surface model is derived with the surface terminated by alternating chains of Si adatoms and Si dimers in between.
|
|
