1
|
Polley CM, Fedderwitz H, Balasubramanian T, Zakharov AA, Yakimova R, Bäcke O, Ekman J, Dash SP, Kubatkin S, Lara-Avila S. Bottom-Up Growth of Monolayer Honeycomb SiC. Phys Rev Lett 2023; 130:076203. [PMID: 36867809 DOI: 10.1103/physrevlett.130.076203] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
The long theorized two-dimensional allotrope of SiC has remained elusive amid the exploration of graphenelike honeycomb structured monolayers. It is anticipated to possess a large direct band gap (2.5 eV), ambient stability, and chemical versatility. While sp^{2} bonding between silicon and carbon is energetically favorable, only disordered nanoflakes have been reported to date. Here we demonstrate large-area, bottom-up synthesis of monocrystalline, epitaxial monolayer honeycomb SiC atop ultrathin transition metal carbide films on SiC substrates. We find the 2D phase of SiC to be almost planar and stable at high temperatures, up to 1200 °C in vacuum. Interactions between the 2D-SiC and the transition metal carbide surface result in a Dirac-like feature in the electronic band structure, which in the case of a TaC substrate is strongly spin-split. Our findings represent the first step towards routine and tailored synthesis of 2D-SiC monolayers, and this novel heteroepitaxial system may find diverse applications ranging from photovoltaics to topological superconductivity.
Collapse
Affiliation(s)
- C M Polley
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - H Fedderwitz
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
| | - T Balasubramanian
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
| | - A A Zakharov
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
| | - R Yakimova
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 581 83 Sweden
| | - O Bäcke
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - J Ekman
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - S P Dash
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - S Kubatkin
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - S Lara-Avila
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| |
Collapse
|
2
|
Lebedev VT, Shakhov FM, Vul AY, Zakharov AA, Zinoviev VG, Orlova VA, Fomin EV. X-ray Excited Optical Luminescence of Eu in Diamond Crystals Synthesized at High Pressure High Temperature. Materials (Basel) 2023; 16:830. [PMID: 36676567 PMCID: PMC9862300 DOI: 10.3390/ma16020830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/29/2022] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Powder diamonds with integrated europium atoms were synthesized at high pressure (7.7 GPa) and temperature (1800 °C) from a mixture of pentaerythritol with pyrolyzate of diphthalocyanine (C64H32N16Eu) being a special precursor. In diamonds prepared by X-ray fluorescence spectroscopy, we have found a concentration of Eu atoms of 51 ± 5 ppm that is by two orders of magnitude greater than that in natural and synthetic diamonds. X-ray diffraction, SEM, X-ray exited optical luminescence, and Raman and IR spectroscopy have confirmed the formation of high-quality diamond monocrystals containing Eu and a substantial amount of nitrogen (~500 ppm). Numerical simulation has allowed us to determine the energy cost of 5.8 eV needed for the incorporation of a single Eu atom with adjacent vacancy into growing diamond crystal (528 carbons).
Collapse
Affiliation(s)
- Vasily T. Lebedev
- B.P.Konstantinov Petersburg Nuclear Physics Institute of NRC Kurchatov Institute, 188300 Gatchina, Russia
| | - Fedor M. Shakhov
- Ioffe Institute, Polytekhnicheskaya Street, 26, 194021 St. Petersburg, Russia
| | - Alexandr Ya. Vul
- Ioffe Institute, Polytekhnicheskaya Street, 26, 194021 St. Petersburg, Russia
| | - Arcady A. Zakharov
- B.P.Konstantinov Petersburg Nuclear Physics Institute of NRC Kurchatov Institute, 188300 Gatchina, Russia
| | - Vladimir G. Zinoviev
- B.P.Konstantinov Petersburg Nuclear Physics Institute of NRC Kurchatov Institute, 188300 Gatchina, Russia
| | | | - Eduard V. Fomin
- B.P.Konstantinov Petersburg Nuclear Physics Institute of NRC Kurchatov Institute, 188300 Gatchina, Russia
| |
Collapse
|
3
|
Kuznetsova NE, Yastremsky AP, Izvin AI, Ponomareva MN, Veshkurtseva IM, Zakharov AA, Izmailova AA. [Evaluation of the possibility of diagnosing purulent-septic rhinogenic complications of the orbit and eyelids in children based on the analysis of clinical and laboratory data]. Vestn Otorinolaringol 2023; 88:56-60. [PMID: 38153894 DOI: 10.17116/otorino20238806156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
OBJECTIVE To study the features of clinical and laboratory parameters of rhinogenic complications of the orbit (RCO) and eyelids depending on the blood leukocyte shift index (LSI) to create a predictive model in pediatric patients. MATERIAL AND METHODS The study included 50 patients who were treated at the Regional Clinical Hospital No. 2 of Tyumen with inflammatory pathology of the paranasal sinuses. Group I with RCO - reactive edema of the eyelids and orbital tissue included 29 (58.0%) patients (of which 16 (32.0%) were boys, 13 (26.0%) were girls). In group 2 with ROC, purulent-septic complications of the eyelids and orbit included 21 (42.0%) patients (of which 10 (20.0%) were boys, 11 (22.0%) were girls). RESULTS LSI values in the general age group (n=50) from 1 to 17 years old were: 1.61 [1.40; 1.82] in patients of group 1; 3.45 [2.96; 3.94] in patients of group 2 (p≤0.05). With an index of LSI from 1.36 to 1.96, the development of reactive edema of the eyelids and orbital tissue is predicted, from 3.14 to 4.72 - the development of purulent-septic complications of the eyelids and orbit in patients of preschool and primary school age. CONCLUSION The marker of clinical and laboratory parameters of the severity of the disease is the LSI indicator, taking into account the age of the child, which can be used in the early diagnosis of purulent-septic rhinogenic complications of the orbit and eyelids in children.
Collapse
Affiliation(s)
| | | | - A I Izvin
- Tyumen State Medical University, Tyumen, Russia
| | | | | | | | | |
Collapse
|
4
|
Aprojanz J, Rosenzweig P, Nguyen TTN, Karakachian H, Küster K, Starke U, Lukosius M, Lippert G, Sinterhauf A, Wenderoth M, Zakharov AA, Tegenkamp C. High-Mobility Epitaxial Graphene on Ge/Si(100) Substrates. ACS Appl Mater Interfaces 2020; 12:43065-43072. [PMID: 32865383 DOI: 10.1021/acsami.0c10725] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
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.
Collapse
Affiliation(s)
- J Aprojanz
- Institut für Physik, Technische Universität Chemnitz, Chemnitz 09126, Germany
| | - Ph Rosenzweig
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - T T Nhung Nguyen
- Institut für Physik, Technische Universität Chemnitz, Chemnitz 09126, Germany
| | - H Karakachian
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - K Küster
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - U Starke
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - M Lukosius
- Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, Frankfurt (Oder) 15236, Germany
| | - G Lippert
- Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, Frankfurt (Oder) 15236, Germany
| | - A Sinterhauf
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - M Wenderoth
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - A A Zakharov
- MAX IV Laboratory and Lund University, Lund 22100, Sweden
| | - C Tegenkamp
- Institut für Physik, Technische Universität Chemnitz, Chemnitz 09126, Germany
| |
Collapse
|
5
|
Laverock J, Jovic V, Zakharov AA, Niu YR, Kittiwatanakul S, Westhenry B, Lu JW, Wolf SA, Smith KE. Observation of Weakened V-V Dimers in the Monoclinic Metallic Phase of Strained VO_{2}. Phys Rev Lett 2018; 121:256403. [PMID: 30608778 DOI: 10.1103/physrevlett.121.256403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/04/2018] [Indexed: 06/09/2023]
Abstract
Emergent order at mesoscopic length scales in condensed matter can provide fundamental insight into the underlying competing interactions and their relationship with the order parameter. Using spectromicroscopy, we show that mesoscopic stripe order near the metal-insulator transition (MIT) of strained VO_{2} represents periodic modulations in both crystal symmetry and V-V dimerization. Above the MIT, we unexpectedly find the long-range order of V-V dimer strength and crystal symmetry become dissociated beyond ≈200 nm, whereas the conductivity transition proceeds homogeneously in a narrow temperature range.
Collapse
Affiliation(s)
- J Laverock
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
| | - V Jovic
- School of Chemical Sciences and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland, Auckland 1142, New Zealand
| | - A A Zakharov
- MAX-lab, Lund University, SE-221 00 Lund, Sweden
| | - Y R Niu
- MAX-lab, Lund University, SE-221 00 Lund, Sweden
| | - S Kittiwatanakul
- Department of Materials Science and Engineering, University of Virginia, Charlottesville,Virginia 22904, USA
- Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - B Westhenry
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - J W Lu
- Department of Materials Science and Engineering, University of Virginia, Charlottesville,Virginia 22904, USA
| | - S A Wolf
- Department of Materials Science and Engineering, University of Virginia, Charlottesville,Virginia 22904, USA
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - K E Smith
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
- School of Chemical Sciences and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland, Auckland 1142, New Zealand
| |
Collapse
|
6
|
Laverock J, Kittiwatanakul S, Zakharov AA, Niu YR, Chen B, Wolf SA, Lu JW, Smith KE. Direct observation of decoupled structural and electronic transitions and an ambient pressure monocliniclike metallic phase of VO2. Phys Rev Lett 2014; 113:216402. [PMID: 25479508 DOI: 10.1103/physrevlett.113.216402] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Indexed: 06/04/2023]
Abstract
We report the simultaneous measurement of the structural and electronic components of the metal-insulator transition (MIT) of VO2 using electron and photoelectron spectroscopies and microscopies. We show that these evolve over different temperature scales, and are separated by an unusual monocliniclike metallic phase. Our results provide conclusive evidence that the new monocliniclike metallic phase, recently identified in high-pressure and nonequilibrium measurements, is accessible in the thermodynamic transition at ambient pressure, and we discuss the implications of these observations on the nature of the MIT in VO2.
Collapse
Affiliation(s)
- J Laverock
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
| | - S Kittiwatanakul
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - A A Zakharov
- MAX-lab, Lund University, SE-221 00 Lund, Sweden
| | - Y R Niu
- MAX-lab, Lund University, SE-221 00 Lund, Sweden
| | - B Chen
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
| | - S A Wolf
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA and Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, USA
| | - J W Lu
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, USA
| | - K E Smith
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA and School of Chemical Sciences and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland, Auckland 1142, New Zealand
| |
Collapse
|
7
|
Zakharov AA. [To the centenary of academician M.S. Giliarov]. Zh Obshch Biol 2013; 74:407-408. [PMID: 25438572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
|
8
|
Vinogradov NA, Zakharov AA, Kocevski V, Rusz J, Simonov KA, Eriksson O, Mikkelsen A, Lundgren E, Vinogradov AS, Mårtensson N, Preobrajenski AB. Formation and structure of graphene waves on Fe(110). Phys Rev Lett 2012; 109:026101. [PMID: 23030182 DOI: 10.1103/physrevlett.109.026101] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Indexed: 06/01/2023]
Abstract
A very rich Fe-C phase diagram makes the formation of graphene on iron surfaces a challenging task. Here we demonstrate that the growth of graphene on epitaxial iron films can be realized by chemical vapor deposition at relatively low temperatures, and that the formation of carbides can be avoided in excess of the carbon-containing precursors. The resulting graphene monolayer creates a novel periodically corrugated pattern on Fe(110). Using low-energy electron microscopy and scanning tunneling microscopy, we show that it is modulated in one dimension forming long waves with a period of ∼4 nm parallel to the [001] direction of the substrate, with an additional height modulation along the wave crests. The observed topography of the graphene/Fe superstructure is well reproduced by density functional theory calculations, and found to result from a unique combination of the lattice mismatch and strong interfacial interaction, as probed by core-level photoemission and x-ray absorption spectroscopy.
Collapse
Affiliation(s)
- N A Vinogradov
- Department of Physics and Astronomy, Uppsala University, Box 530, 75121 Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Kennedy SM, Hjort M, Mandl B, Marsell E, Zakharov AA, Mikkelsen A, Paganin DM, Jesson DE. Characterizing the geometry of InAs nanowires using mirror electron microscopy. Nanotechnology 2012; 23:125703. [PMID: 22397834 DOI: 10.1088/0957-4484/23/12/125703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Mirror electron microscopy (MEM) imaging of InAs nanowires is a non-destructive electron microscopy technique where the electrons are reflected via an applied electric field before they reach the specimen surface. However strong caustic features are observed that can be non-intuitive and difficult to relate to nanowire geometry and composition. Utilizing caustic imaging theory we can understand and interpret MEM image contrast, relating caustic image features to the properties and parameters of the nanowire. This is applied to obtain quantitative information, including the nanowire width via a through-focus series of MEM images.
Collapse
Affiliation(s)
- S M Kennedy
- School of Physics, Monash University, Victoria 3800, Australia
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Vinogradov NA, Zakharov AA, Ng ML, Mikkelsen A, Lundgren E, Mårtensson N, Preobrajenski AB. One-dimensional corrugation of the h-BN monolayer on Fe(110). Langmuir 2012; 28:1775-1781. [PMID: 22185488 DOI: 10.1021/la2035642] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on a new nanopatterned structure represented by a single atomic layer of hexagonal boron nitride (h-BN) forming long periodic waves on the Fe(110) surface. The growth process and the structure of this system are characterized by X-ray absorption (XAS), core-level photoemission spectroscopy (CL PES), low-energy electron microscopy (LEEM), microbeam low-energy electron diffraction (μLEED), and scanning tunneling microscopy (STM). The h-BN monolayer on Fe(110) is periodically corrugated in a wavy fashion with an astonishing degree of long-range order, periodicity of 2.6 nm, and the corrugation amplitude of ∼0.8 Å. The wavy pattern results from a strong chemical bonding between h-BN and Fe in combination with a lattice mismatch in either [111] or [111] direction of the Fe(110) surface. Two primary orientations of h-BN on Fe(110) can be observed corresponding to the possible directions of lattice match between h-BN and Fe(110), with approximately equal area of the boron nitride domains of each orientation.
Collapse
Affiliation(s)
- N A Vinogradov
- Department of Physics and Astronomy, Uppsala University, Box 530, 75121 Uppsala, Sweden
| | | | | | | | | | | | | |
Collapse
|
11
|
Zakharov AA. [The ants: a strategy of population concentration]. Zh Obshch Biol 2011; 72:269-283. [PMID: 21954628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Ants are provided with a balanced system of reactions either to the original paucity of socia or to their secondary depopulation. This system can be defined as a strategy of population concentration. Both a successful reproduction of workers and queen fertilization are necessary conditions for ant communities' survival and development. Thus, the anthills must be large enough to ensure optimal conditions for reproduction. It is the strategy of population concentration that is directed to an accelerated attainment (or rehabilitation) by a socium of a state of stable development by way of concentrating the existent ant staff in an accessible number of viable nests. This strategy is realized throughout the life of ant communities by way of (a) fusing the starting family cells left by founder females, (b) fusing small anthills during artificial ant migrations, (c) uniting smaller socia or their joining other anthills, (d) reintegrating the secondary anthills (fragmentants) after an exogenous fragmentation of formicaries. Pooling and the attraction of deficient demographic resources from outside form the most efficient and quickest ways of reaching or restoring the threshold density levels. By realizing this strategy, the ants solve their paramount problems of anthill or settlement conservation at any particular time, as well as of providing some prospects for ant existence in the future. These problems are so vital for ant socia that they appear to hold priority over such other characteristics of utmost importance as genetic kinship or even species identity. The priority of social basics over genetic ones is unequivocally supported through mixed formicaries. A necessary condition for the realization of the strategy of population concentration is tolerance of highly developed social systems to the diversity of forms and to deviations from the norm. The use of one and the same mechanism at all stages of the life both of an individual socium and large ant settlements is evidence of the universality of this strategy, as well as of its unconditioned importance to the life of ant communities.
Collapse
|
12
|
Markov AV, Zakharov AA, Rodionova NS, Mikhaĭlutsa AA, Strunnikov AV, Smirnov AF. [Correlations of sister chromatids cohesion complexes distribution with histones H3 and H4 modifications]. Tsitologiia 2010; 52:384-388. [PMID: 20586273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The formulation of "histone code" theory brings active investigations of the role of histone modifications and other supramolecular factors of DNA condensation in transcription regulation. In this work, we have analyzed the localization of methylated histones on 9, 36 and 79 lysines, hyperacetylated H4 histone, and subunits of cohesion complex DRAD21 relatively of Drosophila melanogaster polytene chromosomes chromatin condensation. We propose the hypotheses of a cascade regulation of transcription activity defined by histone modifications and the adaptive role of sister chromatids cohesion in the transcription of high active and extensive genes.
Collapse
|
13
|
Riedl C, Coletti C, Iwasaki T, Zakharov AA, Starke U. Quasi-free-standing epitaxial graphene on SiC obtained by hydrogen intercalation. Phys Rev Lett 2009; 103:246804. [PMID: 20366220 DOI: 10.1103/physrevlett.103.246804] [Citation(s) in RCA: 294] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Indexed: 05/11/2023]
Abstract
Quasi-free-standing epitaxial graphene is obtained on SiC(0001) by hydrogen intercalation. The hydrogen moves between the (6 square root(3) x 6 square root(3))R30 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.
Collapse
Affiliation(s)
- C Riedl
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | | | | | | | | |
Collapse
|
14
|
Mikkelsen A, Schwenke J, Fordell T, Luo G, Klünder K, Hilner E, Anttu N, Zakharov AA, Lundgren E, Mauritsson J, Andersen JN, Xu HQ, L'Huillier A. Photoemission electron microscopy using extreme ultraviolet attosecond pulse trains. Rev Sci Instrum 2009; 80:123703. [PMID: 20059146 DOI: 10.1063/1.3263759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We report the first experiments carried out on a new imaging setup, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with the temporal resolution of extreme ultraviolet (XUV) attosecond pulse trains. The very short pulses were provided by high-harmonic generation and used to illuminate lithographic structures and Au nanoparticles, which, in turn, were imaged with a PEEM resolving features below 300 nm. We argue that the spatial resolution is limited by the lack of electron energy filtering in this particular demonstration experiment. Problems with extensive space charge effects, which can occur due to the low probe pulse repetition rate and extremely short duration, are solved by reducing peak intensity while maintaining a sufficient average intensity to allow imaging. Finally, a powerful femtosecond infrared (IR) beam was combined with the XUV beam in a pump-probe setup where delays could be varied from subfemtoseconds to picoseconds. The IR pump beam could induce multiphoton electron emission in resonant features on the surface. The interaction between the electrons emitted by the pump and probe pulses could be observed.
Collapse
Affiliation(s)
- A Mikkelsen
- Department of Physics, Lund University, Box 118, 22100 Lund, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Mikkelsen A, Hilner E, Andersen JN, Ghatnekar-Nilsson S, Montelius L, Zakharov AA. Low temperature Ga surface diffusion from focused ion beam milled grooves. Nanotechnology 2009; 20:325304. [PMID: 19620748 DOI: 10.1088/0957-4484/20/32/325304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Ga diffusion from focused ion beam (FIB) milled grooves has been studied using x-ray photoemission electron microscopy (XPEEM) and mirror electron microscopy (MEM). We analyze the surface chemistry of the FIB structures measuring the Ga presence in the top layers of the milled grooves and morphological defects inside the grooves. The Ga is initially strictly confined to the grooves. However, annealing at temperatures as low as 150 degrees C leads to rapid and significant Ga surface diffusion from the FIB structures. The out-diffused Ga forms a thin layer extending up to several microns laterally in a non-regular pattern. The diffusion is significantly enhanced at small crystallites at the edges of the grooves. We explain the general behavior with an atomic scale model in which interstitial Ga in the milled areas diffuses out and substitutes silanol groups on the surface.
Collapse
Affiliation(s)
- A Mikkelsen
- Synchrotron Radiation Research, Lund University, Box 118, SE-22100 Lund, Sweden.
| | | | | | | | | | | |
Collapse
|
16
|
Markov AV, Zakharov AA, Galkin AP, Strunnikov AV, Smirnov AF. [Localization of cohesin complexes of polytene chromosomes of Drosophila melanogaster located on interbands]. Genetika 2003; 39:1203-11. [PMID: 14582389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The distribution of cohesin complex in polytene chromosomes of Drosophila melanogaster was studied. Cohesin is a complicated protein complex which is regulated by the DRAD21 subunit. Using immunostaining for DRAD21p, the cohesins were shown to be preferentially located in the interband regions. This specificity was not characteristic for puffs, where uniform staining was observed. The presence of a few brightly fluorescent regions (five to ten per chromosome arm) enriched with cohesin complexes was shown. Some of these regions had permanent location, and the others, variable location. No antibody binding was detected in the chromocenter. Immunostaining of interphase nuclei of neuroblasts revealed large cohesin formations. On the polytene chromosomes of D. melanogaster, the Drad21 gene was mapped to the chromocentric region (81) of the L arm of chromosome 3.
Collapse
Affiliation(s)
- A V Markov
- Department of Genetics and Breeding, St. Petersburg State University, St. Petersburg, 199034 Russia
| | | | | | | | | |
Collapse
|
17
|
Zakharov AA, Shevchenko AS. [The use of regional intraarterial therapy in the treatment of the lower extremities open fracture, complicated by purulent infection]. Klin Khir 2000:61-2. [PMID: 10857325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
|
18
|
Zakharov AA, Shevchenko AS, Khanin IV. [Prolonged spinal cord anesthesia with morphine and clofelin]. Klin Khir 2000:59-60. [PMID: 11288258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
|
19
|
Qvarford M, Nazin VG, Zakharov AA, Mikheeva MN, Andersen JN, Johansson MK, Chiaia G, Rogelet T, Söderholm S, Tjernberg O, Nylén H, Lindau I, Nyholm R, Karlsson UO, Barilo SN, Shiryaev SV. Photoemission and x-ray absorption study of superconducting and semiconducting Ba1-xKxBiO3 single crystals. Phys Rev B Condens Matter 1996; 54:6700-6707. [PMID: 9986690 DOI: 10.1103/physrevb.54.6700] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
20
|
Piskunov GZ, Kozhenkova TI, Ageeva OA, Zakharov AA, Zatseda TV. [Malignant external otitis]. Vestn Otorinolaringol 1992:14-6. [PMID: 1589936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
21
|
Sokol BG, Sapozhnikov SM, Zakharov AA, Sheĭnkman EV, Kirsanov IV. [Acute cholecystitis caused by Pseudomonas aeruginosa]. Vestn Khir Im I I Grek 1990; 144:57. [PMID: 2165683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
22
|
Zakharov AA, Shmyreva VF, Pisetskaia SF, Andreev VM. [Dynamics of the aqueous humor in paranasal sinusitis]. Vestn Otorinolaringol 1983:59-62. [PMID: 6857937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
23
|
Zakharov AA. [Dynamic density and the behavior of ants]. Zh Obshch Biol 1975; 36:243-50. [PMID: 1189605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
24
|
Zakharov AA. [Results of surgical treatment of elderly and aged patients with acute cholecystitis]. Vestn Khir Im I I Grek 1974; 113:29-32. [PMID: 4410770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
25
|
Preobrazhenskiĭ NA, Zakharov AA, Sichinava OV. [Use of adenosine triphosphate in sudden deafness]. Vestn Otorinolaringol 1971; 33:32-7. [PMID: 5112393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|