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Rohrer GS, Henrich VE, Bonnell DA. A Scanning Tunneling Microscopy Study of the Reduced Tio2(110)Surface. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-209-611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe scanning tunneling microscope has been used to image a reduced TiO2(110) surface in ultrahigh vacuum. Structural units with periodicities ranging from 21Å to 3.4Å have been clearly imaged and the observed surface structures can be explained by a model involving ordered arrangements of two dimensional defects known as crystallographic shear planes. An electronic state 0.5 eV below the conduction band edge, detected in tunneling spectra, has been assigned to reduced Ti cations which reside along the crystallographic shear planes. This state appears to be empty at the surface, possibly due to asmall amount of band bending. The results indicate that the topography of nonstoichiometric oxide surfaces can be rather complex and that the tunneling microscope provides an effective tool for studying the tomic scale surface features of wide band gap semiconductors.
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Lieber CM, Yang P. High-Temperature Superconductors. Science 1997. [DOI: 10.1126/science.277.5334.1909-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Charles M. Lieber
- Department of Chemistry,
Harvard University,
Cambridge, MA 02138, USA
| | - Peidong Yang
- Department of Chemistry,
Harvard University,
Cambridge, MA 02138, USA
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Affiliation(s)
- R. J. Hamers
- Department of Chemistry, University of WisconsinMadison, 1101 University Avenue, Madison, Wisconsin 53706
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Lieber CM, Liu J, Sheehan PE. Anorganische Materialien mit Hilfe von Rastersondenmikroskopen verstehen und manipulieren. Angew Chem Int Ed Engl 1996. [DOI: 10.1002/ange.19961080704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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6
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Electron tunneling microscopy: a direct probe of metal substitution in BiSrCaCuO superconductors. Inorganica Chim Acta 1996. [DOI: 10.1016/0020-1693(95)04920-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ma J, Alméras P, Kelley RJ, Berger H, Margaritondo G, Cai XY, Feng Y, Onellion M. Pb0.4Bi1.6Sr2CaCu2O8+x and oxygen stoichiometry: Structure, resistivity, Fermi-surface topology, and normal-state properties. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:9271-9285. [PMID: 9977569 DOI: 10.1103/physrevb.51.9271] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Koguchi K, Matsumoto T, Kawai T. Atomic-Scale Images of the Growth Surface of Ca
1–
x
Sr
x
CuO
2
Thin Films. Science 1995; 267:71-3. [PMID: 17840060 DOI: 10.1126/science.267.5194.71] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The surface microstructure of c-axis (Ca,Sr)CuO(2) thin films, grown by laser molecular beam epitaxy on SrTiO(3)(001) substrates, was studied by ultrahigh-vacuum scanning tunneling microscopy (STM). Images were obtained for codeposited Ca1-xSrxCuO(2) thin films, which show a layered-type growth mode. The surfaces consist of atomically flat terraces separated by steps that are one unit cell high. A pronounced dependence of the growth mechanism on the Sr/Ca ratio of the films was observed. Atomic resolution STM images of the CuO(2) sheets in the ab plane show a square lattice with an in-plane spacing of 4 angstroms; the lattice contains different concentrations of point defects, depending on the polarity of the sample-tip bias.
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Balzarotti A, Fanfoni M, Patella F, Sgarlata A, Sperduti R. Microscopic aspects of the Fe/Bi2Sr2CaCu2O8 reactive interface. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:9103-9110. [PMID: 10009692 DOI: 10.1103/physrevb.49.9103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Determination of modulation wavelengths in nanoscale electrodeposited superlattices using the scanning tunneling microscope. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0965-9773(93)90023-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Zhang Z, Lieber CM. Measurement of the energy gap in oxygen-annealed Bi2Sr2CaCu2O8+ delta high-Tc superconductors by tunneling spectroscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:3423-3426. [PMID: 10006433 DOI: 10.1103/physrevb.47.3423] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Switzer JA, Raffaelle RP, Phillips RJ, Hung CJ, Golden TD. Scanning Tunneling Microscopy of Electrodeposited Ceramic Superlattices. Science 1992; 258:1918-21. [PMID: 17836184 DOI: 10.1126/science.258.5090.1918] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Cleaved cross sections of nanometer-scale ceramic superlattices fabricated from materials of the lead-thallium-oxygen system were imaged in the scanning tunneling microscope (STM). The apparent height differences between the layers were attributed to composition-dependent variations in local electrical properties. For a typical superlattice, the measured modulation wavelength was 10.6 nanometers by STM and 10.8 nanometers by x-ray diffraction. The apparent height profile for potentiostatically deposited superlattices was more square than that for galvanostatically deposited samples. These results suggest that the composition follows the applied potential more closely than it follows the applied current. The x-ray diffraction pattern of a superlattice produced under potential control had satellites out to the fourth order around the (420) Bragg reflection.
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Munakata F, Kawano T, Yamauchi H, Inoue Y. Relationship between oxygen nonstoichiometry and structural changes in Bi-2212 superconductors. J SOLID STATE CHEM 1992. [DOI: 10.1016/0022-4596(92)90198-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zhang Z, Lieber CM. Oxygen doping Bi2Sr2CaCu2O8+ delta superconductors: Variations in the BiO-layer electronic states determined by scanning tunneling microscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:5845-5848. [PMID: 10004396 DOI: 10.1103/physrevb.46.5845] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Li Y, Huang JL, Lieber CM. Temperaure dependence of the energy gap in Bi2Sr2CaCu2O8 superconductors by high-resolution electron-energy-loss spectroscopy. PHYSICAL REVIEW LETTERS 1992; 68:3240-3243. [PMID: 10045649 DOI: 10.1103/physrevlett.68.3240] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Zhang Z, Chen CC, Lieber CM, Morosin B, Ginley DS, Venturini EL. Relationship between crystal chemistry and the local structure and electronic properties of Tl2Ba2Ca2Cu3O10 superconductors determined by scanning tunneling microscopy and spectroscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 45:987-992. [PMID: 10001142 DOI: 10.1103/physrevb.45.987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Szunyogh L, Hörmandinger G, Weinberger P. Effects of nonstoichiometry, ordering, and Bi substitution with Pb in Bi2Sr2CaCu2O8. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 43:13025-13031. [PMID: 9997122 DOI: 10.1103/physrevb.43.13025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Shih CK, Feenstra RM, Chandrashekhar GV. Scanning tunneling microscopy and spectroscopy of Bi-Sr-Ca-Cu-O 2:2:1:2 high-temperature superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 43:7913-7922. [PMID: 9996413 DOI: 10.1103/physrevb.43.7913] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wu XL, Wang YL, Zhang Z, Lieber CM. Electronic and structural effects of oxygen doping in Bi2Sr2CaCu2Ox superconductors characterized by tunneling microscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 43:8729-8732. [PMID: 9996532 DOI: 10.1103/physrevb.43.8729] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Rohrer GS, Henrich VE, Bonnell DA. Structure of the Reduced TiO2(110) Surface Determined by Scanning Tunneling Microscopy. Science 1990; 250:1239-41. [PMID: 17829209 DOI: 10.1126/science.250.4985.1239] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The scanning tunneling microscope has been used to image a reduced TiO(2)(110) surface in ultrahigh vacuum. Structural units with periodicities rangng from 21 to 3.4 angstroms have been clearly imaged, demonstrating that atomic resolution imaging of an ionic, wide band gap (3.2 electron volts) semiconductor is possible. The observed surface structures can be explained by a model involving ordered arrangements of two-dimensional defects known as crystallographic shear planes and indicate that the topography of nonstoichiometric oxide surfaces can be complex.
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Wang YL, Wu XL, Chen CC, Lieber CM. Enhancement of the critical current density in single-crystal Bi2Sr2CaCu2O8 superconductors by chemically induced disorder. Proc Natl Acad Sci U S A 1990; 87:7058-60. [PMID: 11607103 PMCID: PMC54682 DOI: 10.1073/pnas.87.18.7058] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The effect of metal substitution on the critical current densities of single-crystal PbxBi2-xSr2CaCu2O8 (x = 0 or x = 0.7) superconductors has been investigated. Substitution of lead was found to increase the average critical current density from 1 x 10(5) A/cm2 to 2 x 10(6) A/cm2 at 5 K in an applied magnetic field of 10 kilooersteds (1 oersted = 80 A/m). The order of magnitude increase in the critical current density was observed for temperatures up to the flux vortex lattice melting point; the flux lattice melting point was also found to increase to 30 K (from 22 K) in the lead-substituted materials. Diffraction and microscopy investigations of the structural parameters indicate that the fundamental atomic lattices are virtually the same for both materials. Scanning tunneling microscopy images demonstrate, however, that lead substitution causes significant disorder (or defects) in the one-dimensional superstructure found in Bi2Sr2CaCu2O8. Since crystal defects can increase the critical current density by pinning the motion of flux vortices, it is likely that this lead-induced disorder enhances vortex pinning. The lead-induced disorder is specific to the nonsuperconducting Bi-O layers, and thus our results suggest that chemical substitutions may be utilized to control selectively flux pinning and the critical current density in these materials.
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Affiliation(s)
- Y L Wang
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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Ogletree F, Salmeron M. Scanning tunneling microscopy and the atomic structure of solid surfaces. PROG SOLID STATE CH 1990. [DOI: 10.1016/0079-6786(90)90002-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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