1
|
Do EH, Kwon SG, Kang MH, Yeom HW. Structural and electronic effects of adatoms on metallic atomic chains in Si(111)5 × 2-Au. Sci Rep 2018; 8:15537. [PMID: 30341308 PMCID: PMC6195602 DOI: 10.1038/s41598-018-33703-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/02/2018] [Indexed: 11/21/2022] Open
Abstract
We investigate the effects of native Si adatoms on structural and electronic properties of the Si(111)5 × 2-Au surface, a representative one-dimensional metal-chain system, by means of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. High-resolution STM images of relatively long adatom-free chain segments evidence directly the inherent ×2 reconstruction, which is the essential part of a recently proposed structural model based on a renewed Au coverage of 0.7 monolayer. On the other hand, STM images for chain segments of different lengths reveal that the structural distortion induced by Si adatoms is confined in neighboring unit cells, in good agreement with DFT calculations based on that model. Si adatoms greatly affect the metallic bands of Au chains, one of which becomes fully occupied and represents a tightly confined electronic state to the distortion around Si adatoms, potentially forming short insulating segments within metallic chains. This finding provides an atomic-scale understanding of the observed gradual metal-insulator transition and atomic-scale phase separation induced by Si adatoms.
Collapse
Affiliation(s)
- Eui Hwan Do
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea. .,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| | - Se Gab Kwon
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Myung Ho Kang
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea. .,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| |
Collapse
|
2
|
Koirala P, Lin Y, Ciston J, Marks LD. When does atomic resolution plan view imaging of surfaces work? Ultramicroscopy 2016; 170:35-42. [PMID: 27526257 DOI: 10.1016/j.ultramic.2016.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 07/07/2016] [Accepted: 08/05/2016] [Indexed: 11/16/2022]
Abstract
Surface structures that are different from the corresponding bulk, reconstructions, are exceedingly difficult to characterize with most experimental methods. Scanning tunneling microscopy, the workhorse for imaging complex surface structures of metals and semiconductors, is not as effective for oxides and other insulating materials. This paper details the use of transmission electron microscopy plan view imaging in conjunction with image processing for solving complex surface structures. We address the issue of extracting the surface structure from a weak signal with a large bulk contribution. This method requires the sample to be thin enough for kinematical assumptions to be valid. The analysis was performed on two sets of data, c(6×2) on the (100) surface and (3×3) on the (111) surface of SrTiO3, and was unsuccessful in the latter due to the thickness of the sample and a lack of inversion symmetry. The limits and the functionality of this method are discussed.
Collapse
Affiliation(s)
- Pratik Koirala
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yuyuan Lin
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Jim Ciston
- National Center for Electron Microscopy, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Laurence D Marks
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.
| |
Collapse
|
3
|
Ciston J, Brown HG, D'Alfonso AJ, Koirala P, Ophus C, Lin Y, Suzuki Y, Inada H, Zhu Y, Allen LJ, Marks LD. Surface determination through atomically resolved secondary-electron imaging. Nat Commun 2015; 6:7358. [PMID: 26082275 PMCID: PMC4557350 DOI: 10.1038/ncomms8358] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/29/2015] [Indexed: 11/30/2022] Open
Abstract
Unique determination of the atomic structure of technologically relevant surfaces is often limited by both a need for homogeneous crystals and ambiguity of registration between the surface and bulk. Atomically resolved secondary-electron imaging is extremely sensitive to this registration and is compatible with faceted nanomaterials, but has not been previously utilized for surface structure determination. Here we report a detailed experimental atomic-resolution secondary-electron microscopy analysis of the c(6 × 2) reconstruction on strontium titanate (001) coupled with careful simulation of secondary-electron images, density functional theory calculations and surface monolayer-sensitive aberration-corrected plan-view high-resolution transmission electron microscopy. Our work reveals several unexpected findings, including an amended registry of the surface on the bulk and strontium atoms with unusual seven-fold coordination within a typically high surface coverage of square pyramidal TiO5 units. Dielectric screening is found to play a critical role in attenuating secondary-electron generation processes from valence orbitals.
Collapse
Affiliation(s)
- J. Ciston
- National Center for Electron Microscopy, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - H. G. Brown
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - A. J. D'Alfonso
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - P. Koirala
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - C. Ophus
- National Center for Electron Microscopy, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Y. Lin
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Y. Suzuki
- Application Development Department, Hitachi High Technologies Corp., Ibaraki 312-8504, Japan
| | - H. Inada
- Advanced Microscope Design Department, Hitachi High Technologies Corp., Ibaraki 312-8504, Japan
| | - Y. Zhu
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - L. J. Allen
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - L. D. Marks
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| |
Collapse
|
4
|
Shirasawa T, Voegeli W, Nojima T, Iwasawa Y, Yamaguchi Y, Takahashi T. Identification of the structure model of the Si(111)-(5 × 2)-Au surface. PHYSICAL REVIEW LETTERS 2014; 113:165501. [PMID: 25361265 DOI: 10.1103/physrevlett.113.165501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Indexed: 06/04/2023]
Abstract
The atomic structure of the Si(111)-(5 × 2)-Au surface, a periodic gold chain on the silicon surface, has been a long-debated issue in surface science. The recent three candidates, the so-called Erwin-Barke-Himpsel (EBH) model [S. C. Erwin, I. Barke, and F. J. Himpsel, Phys. Rev. B 80, 155409 (2009)], the Abukawa-Nishigaya (AN) model [T. Abukawa and Y. Nishigaya, Phys. Rev. Lett. 110, 036102 (2013)], and the Kwon-Kang (KK) model [S. G. Kwon and M. H. Kang, Phys. Rev. Lett. 113, 086101 (2014)] that has one additional Au atom than the EBH model are tested by surface x-ray diffraction data. A two-dimensional Patterson map constructed from the in-plane diffraction intensities rejects the AN model and prefers the KK model over the EBH model. On the basis of the arrangement of Au obtained from the Patterson map, all the reconstructed Si atoms, such as the so-called honeycomb chain structure, are directly imaged out by utilizing a holographic method. The KK model reproduces out-of-plane diffraction data as well.
Collapse
Affiliation(s)
- Tetsuroh Shirasawa
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan and JST, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Wolfgang Voegeli
- Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-0015, Japan
| | - Takehiro Nojima
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Yusaku Iwasawa
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Yudai Yamaguchi
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Toshio Takahashi
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| |
Collapse
|
5
|
Subramanian G, Basu S, Liu H, Zuo JM, Spence JCH. Solving protein nanocrystals by cryo-EM diffraction: multiple scattering artifacts. Ultramicroscopy 2014; 148:87-93. [PMID: 25461585 DOI: 10.1016/j.ultramic.2014.08.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 08/27/2014] [Accepted: 08/31/2014] [Indexed: 02/04/2023]
Abstract
The maximum thickness permissible within the single-scattering approximation for the determination of the structure of perfectly ordered protein microcrystals by transmission electron diffraction is estimated for tetragonal hen-egg lysozyme protein crystals using several approaches. Multislice simulations are performed for many diffraction conditions and beam energies to determine the validity domain of the required single-scattering approximation and hence the limit on crystal thickness. The effects of erroneous experimental structure factor amplitudes on the charge density map for lysozyme are noted and their threshold limits calculated. The maximum thickness of lysozyme permissible under the single-scattering approximation is also estimated using R-factor analysis. Successful reconstruction of density maps is found to result mainly from the use of the phase information provided by modeling based on the protein data base through molecular replacement (MR), which dominates the effect of poor quality electron diffraction data at thicknesses larger than about 200 Å. For perfectly ordered protein nanocrystals, a maximum thickness of about 1000 Å is predicted at 200 keV if MR can be used, using R-factor analysis performed over a subset of the simulated diffracted beams. The effects of crystal bending, mosaicity (which has recently been directly imaged by cryo-EM) and secondary scattering are discussed. Structure-independent tests for single-scattering and new microfluidic methods for growing and sorting nanocrystals by size are reviewed.
Collapse
Affiliation(s)
- Ganesh Subramanian
- Department of Materials Science and Engineering, Arizona State University, Tempe, AZ, USA
| | - Shibom Basu
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, USA
| | - Haiguang Liu
- Department of Physics, Arizona State University, Tempe, AZ 85287-1504, USA
| | - Jian-Min Zuo
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, USA
| | - John C H Spence
- Department of Physics, Arizona State University, Tempe, AZ 85287-1504, USA.
| |
Collapse
|
6
|
Kwon SG, Kang MH. Identification of the au coverage and structure of the Au/Si(111)-(5 × 2) surface. PHYSICAL REVIEW LETTERS 2014; 113:086101. [PMID: 25192108 DOI: 10.1103/physrevlett.113.086101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Indexed: 06/03/2023]
Abstract
We identify the atomic structure of the Au/Si(111)-(5 × 2) surface by using density functional theory calculations. With seven Au atoms per unit cell, our model forms a bona fide (5 × 2) atomic structure, which is energetically favored over the leading model of Erwin et al. [Phys. Rev. B 80, 155409 (2009)], and well reproduces the Y-shaped and V-shaped (5 × 2) STM images. This surface is metallic with a prominent half filled band of surface states, mostly localized around the Au-chain area. The correct identification of the atomic and band structure of the clean surface further clarifies the adsorption structure of Si adatoms and the physical origin of the intriguing metal-to-insulator transition driven by Si adatoms.
Collapse
Affiliation(s)
- Se Gab Kwon
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Myung Ho Kang
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| |
Collapse
|
7
|
Abukawa T, Nishigaya Y. Structure of the Si(111)-(5×2)-Au surface. PHYSICAL REVIEW LETTERS 2013; 110:036102. [PMID: 23373937 DOI: 10.1103/physrevlett.110.036102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Indexed: 06/01/2023]
Abstract
The structure of the Si(111)-(5×2)-Au surface, one of the long-standing problems in surface science, has been solved by means of Weissenberg reflection high-energy electron diffraction. The arrangement of the Au atoms and their positions with respect to the substrate were determined from a three-dimensional Patterson function with a lateral resolution of 0.3 Å based on a large amount of diffraction data. The new structural model consists of six Au atoms in a 5×2 unit, which agrees with the recently confirmed Au coverage of 0.6 ML [I. Barke et al., Phys. Rev. B 79, 155301 (2009).]. The model has a distinct ×2 periodicity, and includes a Au dimer. The model is also compatible with previously obtained STM images.
Collapse
Affiliation(s)
- Tadashi Abukawa
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | | |
Collapse
|
8
|
Stępniak A, Krawiec M, Zawadzki G, Jałochowski M. Electronic stabilization of the Si(111)5 × 2-Au surface: Pb and Si adatoms. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:095002. [PMID: 22274993 DOI: 10.1088/0953-8984/24/9/095002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Using scanning tunneling microscopy/spectroscopy (STM/STS), angle resolved photoemission spectroscopy (ARPES) and first-principles density functional theory (DFT), we study the structural and the electronic properties of the Si(111)5 × 2-Au surface decorated with Pb adatoms. The STM topography data reveal that Pb adatoms form a similar superstructure to that observed in the case of Si adatoms on a bare Si(111)5 × 2-Au surface. The DFT calculations show that preferential adsorption sites of Pb atoms are located near the double Au chain. Bias dependent STM topography and spectroscopy together with the DFT calculations allow us to distinguish Pb from Si adatoms. Both the Si and Pb adatoms modify the electronic properties in the same way, which confirms the electronic origin of the stabilization of the surface.
Collapse
Affiliation(s)
- A Stępniak
- Institute of Physics, M Curie-Skłodowska University, Place M Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | | | | | | |
Collapse
|
9
|
Regular Array of L-Tyrosine Molecules on Si(111)-Au Superstructures. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2010. [DOI: 10.1380/ejssnt.2010.303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
10
|
McAlinden N, McGilp JF. Using surface and interface optics to probe the capping, with amorphous Si, of Au atom chains grown on vicinal Si(111). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:474208. [PMID: 21832487 DOI: 10.1088/0953-8984/21/47/474208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The distinct optical signatures of aligned single and double Au atom chain structures, grown on vicinal Si(111) substrates, have been identified using reflectance anisotropy spectroscopy (RAS). Deposition of 0.04 monolayers (ML) of amorphous Si (a-Si) at room temperature perturbs the anisotropic optical response of the double chain structure. By one third of a monolayer, no significant optical anisotropy associated with the chains remains. No anisotropic response re-emerges at higher coverages, up to 4.6 nm (14.5 ML) where there is recent evidence that the crystal structure of the double chain phase is maintained under the cap. The RAS results show that the anisotropic properties of the phase are quenched by a-Si adsorption, even though the crystal structure of the capped phase appears to be preserved.
Collapse
Affiliation(s)
- N McAlinden
- School of Physics, Trinity College Dublin, Dublin 2, Republic of Ireland
| | | |
Collapse
|
11
|
Kang PG, Jeong H, Yeom HW. Hopping domain wall induced by paired adatoms on an atomic wire: si(111)-(5 x 2)-Au. PHYSICAL REVIEW LETTERS 2008; 100:146103. [PMID: 18518054 DOI: 10.1103/physrevlett.100.146103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Indexed: 05/26/2023]
Abstract
We observed an inhomogeneous fluctuation along one-dimensional atomic wires self-assembled on a Si(111) surface using scanning tunneling microscopy. The fluctuation exhibits dynamic behavior at room temperature and is observed only in a specific geometric condition; the spacing between two neighboring adatom defects is discommensurate with the wire lattice. Upon cooling, the dynamic fluctuation freezes to show the existence of an atomic-scale dislocation or domain wall induced by such "unfavorably" paired adatoms. The microscopic characteristics of the dynamic fluctuation are explained in terms of a hopping solitonic domain wall, and a local potential for this motion imposed by the adatoms is quantified.
Collapse
Affiliation(s)
- Pil-Gyu Kang
- Institute of Physics and Applied Physics and Center for Atomic Wires and Layers, Yonsei University, Seoul 120-749, Korea
| | | | | |
Collapse
|
12
|
Yoon HS, Park SJ, Lee JE, Whang CN, Lyo IW. Novel electronic structure of inhomogeneous quantum wires on a Si surface. PHYSICAL REVIEW LETTERS 2004; 92:096801. [PMID: 15089498 DOI: 10.1103/physrevlett.92.096801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Indexed: 05/24/2023]
Abstract
A one-dimensional system of Si(111)-(5 x 2)-Au is explored using scanning tunneling microscopy and spectroscopy. The chain of Si adatoms called bright protrusions (BP's) is found to be semiconducting with an evanescent state in the gap, which originates from adjoining metallic BP-free segments. A quantitative analysis shows that the evanescent state decays in inverse-Gaussian form, leading to an appearance of a parabolic BP chain, and scales to its chain length. Spatial decay of the state suggests a quadratic band bending and the existence of a Schottky-like potential barrier at the interface driven by charge transfer.
Collapse
Affiliation(s)
- H S Yoon
- Atomic-scale Surface Science Research Center and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | | | | | | | | |
Collapse
|
13
|
Subramanian A, Marks LD. Surface crystallography via electron microscopy. Ultramicroscopy 2004; 98:151-7. [PMID: 15046794 DOI: 10.1016/j.ultramic.2003.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2003] [Revised: 07/08/2003] [Indexed: 10/27/2022]
Abstract
The study of atomic structure of surfaces is fundamental to the understanding of electronic, chemical and mechanical properties of surfaces and numerous techniques have been developed to this end. Transmission Electron Microscopy techniques, namely transmission electron imaging (TEM) and diffraction (TED), due to their ability to provide structural information at very high resolutions, have emerged as powerful tools for the study of surface structure. In this article we review the experimental method alongside the various post-processing routines that are necessary to extract vital structural information from experimental data.
Collapse
Affiliation(s)
- A Subramanian
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Dr, Cook Hall #2036, Evanston, IL 60208-3108, USA.
| | | |
Collapse
|
14
|
Erwin SC. Self-doping of gold chains on silicon: a new structural model for Si(111)-(5 x 2)-Au. PHYSICAL REVIEW LETTERS 2003; 91:206101. [PMID: 14683377 DOI: 10.1103/physrevlett.91.206101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2003] [Indexed: 05/24/2023]
Abstract
A new structural model for the Si(111)-(5 x 2)-Au reconstruction is proposed and analyzed using first-principles calculations. The basic model consists of a "double honeycomb chain" decorated by Si adatoms. The 5 x 1 periodicity of the honeycomb chains is doubled by the presence of a half-occupied row of Si atoms that partially rebonds the chains. Additional adatoms supply electrons that dope the parent band structure and stabilize the period doubling; the optimal doping corresponds to one adatom per four 5 x 2 cells, in agreement with experiment. All the main features observed in scanning tunneling microscopy and photoemission are well reproduced.
Collapse
Affiliation(s)
- Steven C Erwin
- Center for Computational Materials Science, Naval Research Laboratory, Washington, DC 20375, USA
| |
Collapse
|
15
|
Erdman N, Poeppelmeier KR, Asta M, Warschkow O, Ellis DE, Marks LD. The structure and chemistry of the TiO(2)-rich surface of SrTiO(3) (001). Nature 2002; 419:55-8. [PMID: 12214229 DOI: 10.1038/nature01010] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oxide surfaces are important for applications in catalysis and thin film growth. An important frontier in solid-state inorganic chemistry is the prediction of the surface structure of an oxide. Comparatively little is known about atomic arrangements at oxide surfaces at present, and there has been considerable discussion concerning the forces that control such arrangements. For instance, one model suggests that the dominant factor is a reduction of Coulomb forces; another favours minimization of 'dangling bonds' by charge transfer to states below the Fermi energy. The surface structure and properties of SrTiO(3)--a standard model for oxides with a perovskite structure--have been studied extensively. Here we report a solution of the 2 x 1 SrTiO(3) (001) surface structure obtained through a combination of high-resolution electron microscopy and theoretical direct methods. Our results indicate that surface rearrangement of TiO(6-x) units into edge-sharing blocks determines the SrO-deficient surface structure of SrTiO(3). We suggest that this structural concept can be extended to perovskite surfaces in general.
Collapse
Affiliation(s)
- Natasha Erdman
- Department of Materials Science and Engineering, Institute for Environmental Catalysis, Northwestern University, Evanston, Illinois 60208-3108, USA
| | | | | | | | | | | |
Collapse
|
16
|
Robinson IK, Bennett PA, Himpsel FJ. Structure of quantum wires in Au/Si(557). PHYSICAL REVIEW LETTERS 2002; 88:096104. [PMID: 11864033 DOI: 10.1103/physrevlett.88.096104] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2001] [Indexed: 05/23/2023]
Abstract
The structure of the Au/Si(557) surface is determined from three-dimensional x-ray diffraction measurements, which directly mandate a single Au atom per unit cell. We use a "heavy atom" method in which the Au atom images the rest of the structure. Au is found to substitute for a row of first-layer Si atoms in the middle of the terrace, which then reconstructs by step rebonding and adatoms. The structure is consistent with the 1D metallic behavior seen by photoemission.
Collapse
Affiliation(s)
- I K Robinson
- Department of Physics, University of Illinois, Urbana, IL 61801, USA
| | | | | |
Collapse
|
17
|
|
18
|
Leslie C, Landree E, Collazo-Davila C, Bengu E, Grozea D, Marks LD. Electron crystallography in surface structure analysis. Microsc Res Tech 1999; 46:160-77. [PMID: 10420173 DOI: 10.1002/(sici)1097-0029(19990801)46:3<160::aid-jemt2>3.0.co;2-#] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Surface structure analysis is an important area of research, and in recent years notable advances have been made in this field, both in improved techniques for studying surfaces and in methods of analyzing them. This review aims to summarize the techniques available, particularly those relating to electron microscopy, and also to outline one of the newest areas of development, the application of direct methods to surface structure analysis.
Collapse
Affiliation(s)
- C Leslie
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | | | | | | | | | | |
Collapse
|
19
|
Affiliation(s)
- C. Leslie
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - E. Landree
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - C. Collazo‐Davila
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - E. Bengu
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - D. Grozea
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - L. D. Marks
- Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| |
Collapse
|
20
|
Grozea D, Landree E, Collazo-Davila C, Bengu E, Plass R, Marks L. Structural investigations of metal–semiconductor surfaces. Micron 1999. [DOI: 10.1016/s0968-4328(98)00039-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
21
|
Bengu E, Collazo-Davila C, Grozea D, Landree E, Widlow I, Guruz M, Marks LD. In situ growth and characterization of ultrahard thin films. Microsc Res Tech 1998; 42:295-301. [PMID: 9779834 DOI: 10.1002/(sici)1097-0029(19980915)42:4<295::aid-jemt8>3.0.co;2-p] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Results concerning the operation of a new ultrahigh vacuum (UHV) ion-beam assisted deposition system for in situ investigation of ultrahard thin films are reported. A molecular beam epitaxy (MBE) chamber attached to a surface science system (SPEAR) has been redesigned for deposition of cubic-boron nitride thin films. In situ thin film processing capability of the overall system is demonstrated in preliminary studies on deposition of boron nitride films on clean Si (001) substrates, combining thin film growth with electron microscopy and surface characterization, all in situ.
Collapse
Affiliation(s)
- E Bengu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | | | | | | | | | | | | |
Collapse
|
22
|
Hasegawa S, Jiang CS, Tong X, Nakajima Y. Electrical functional properties of surface superstructures on semiconductors. Adv Colloid Interface Sci 1997. [DOI: 10.1016/s0001-8686(97)90014-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
23
|
Kamino T, Yaguchi T, Tomita M, Saka H. In-situhigh-resolution electron microscopy study on a surface reconstruction of Au-deposited Si at very high temperatures. ACTA ACUST UNITED AC 1997. [DOI: 10.1080/01418619708210285] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
24
|
Bengu E, Plass R, Marks LD, Ichihashi T, Ajayan PM, Iijima S. Imaging the Dimers in Si(111)-(7 x 7). PHYSICAL REVIEW LETTERS 1996; 77:4226-4228. [PMID: 10062480 DOI: 10.1103/physrevlett.77.4226] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
25
|
Jiang CS, Hasegawa S, Ino S. Surface conductivity for Au or Ag on Si(111). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:10389-10392. [PMID: 9984831 DOI: 10.1103/physrevb.54.10389] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
26
|
Weitering HH, Shi X, Erwin SC. Band dispersions of the pi -bonded-chain reconstruction of Si(111)3 x 1-Li: A critical evaluation of theory and experiment. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:10585-10592. [PMID: 9984854 DOI: 10.1103/physrevb.54.10585] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
27
|
Hasegawa T, Hosoki S. Intrarow diffusion of Au atoms in the Si(111)-(5 x 2)Au structure. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:10300-10303. [PMID: 9984808 DOI: 10.1103/physrevb.54.10300] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|