Imaging of the Hydrogen Subsurface Site in Rutile<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>TiO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>

Enevoldsen, Georg H.; Pinto, Henry P.; Foster, Adam S.; Jensen, Mona C. R.; Hofer, Werner A.; Hammer, Bjørk; Lauritsen, Jeppe V.; Besenbacher, Flemming

doi:10.1103/physrevlett.102.136103

Cited by 87 publications

(64 citation statements)

References 25 publications

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“…The presence of surface and subsurface defects in insulating oxide surfaces has recently been highlighted, 60,70,71 and it will be critical to study how these affect the interaction of water with the surface.…”

Section: Discussionmentioning

confidence: 99%

Structure and diffusion of intrinsic defects, adsorbed hydrogen, and water molecules at the surface of alkali-earth fluorides calculated using density functional theory

2009

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Section: Discussionmentioning

confidence: 99%

Structure and diffusion of intrinsic defects, adsorbed hydrogen, and water molecules at the surface of alkali-earth fluorides calculated using density functional theory

2009

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“…Intuitively, NC-AFM imaging with charged tips appears as the ideal tool to study defect formation in ionic materials, 36,51,52 since charged tips are highly sensitive to even very small variations in the charge distribution in the surface. The cation inversion process on the Al sites, which is summarized as Al X Al → Mg Al , effectively redistributes the charges associated with Mg 2+ and Al 3+ , so that Mg Al exposed to the surface has a 1-unit charge lower than the surrounding Al.…”

Section: Nc-afm Contrast Of Surface Defects On Mgal 2 O 4 (100)mentioning

confidence: 99%

Noncontact atomic force microscopy imaging of atomic structure and cation defects of the polar MgAl2O4(100) surface: Experiments and first-principles simulations

et al. 2011

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version of the following article: Rasmussen, Morten K. ; Foster, Adam S. ; Canova, Filippo F. ; Hinnemann, Berit ; Helveg, Stig ; Meinander, Kristoffer ; Besenbacher, Flemming ; Lauritsen, Jeppe V.. 2011. Noncontact atomic force microscopy imaging of atomic structure and cation defects of the polar MgAl2O4 (100) All material supplied via Aaltodoc is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. Atom-resolved noncontact atomic force microscopy (NC-AFM) was recently used to reveal that the insulating spinel MgAl 2 O 4 (100) surface, when prepared under vacuum conditions, adopts a structurally well-defined Al and O-rich structure (Al 4 -O 4 -Al 4 termination) consisting of alternating Al and double-O rows, which are, however, interrupted by defects identified as interchanged Mg in the surface layers (so-called antisite defects). From an interplay of futher NC-AFM experiments and first-principles NC-AFM image simulations, we present here a detailed analysis of the NC-AFM contrast on the MgAl 2 O 4 (100) surface. Experiments show that the contrast on MgAl 2 O 4 (100) in atom-resolved NC-AFM is dominated by two distinctly different types of contrast modes, reflecting two oppositely charged tip-apex terminations. In this paper, we analyze the contrast associated with these imaging modes and show that a positively charged tip-apex (presumably Mg 2+ ) interacts most strongly with the oxygen atoms, thus imaging the oxygen lattice, whereas a negatively charged tip-apex (O 2− ) will reveal the cation sublattice on MgAl 2 O 4 . The analysis of force-vs-distance calculations for the two tips shows that this qualitative picture, developed in our previous study, holds for all realistic tip-surface imaging parameters, but the detailed resolution on the O double rows and Al rows changes as a function of tip-surface distance, which is also observed experimentally. We also provide an analysis of the tip dependency and tip-surface distance dependency for the NC-AFM contrast associated with single Al vacancies and Mg-Al antisite defects on the MgAl 2 O 4 (100) surface and show that it is possible on the basis of NC-AFM image simulations to discriminate between the Al 3+ and Mg 2+ species in antisite defects and hypothetical Al vacancies.

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“…The interaction of hydrogen with wide band gap oxides and minerals is important for many applications and has been the subject of a number of experimental and theoretical studies (see refs. [1][2][3][4][5][6][7], to mention a few). Among these oxides, quartz and amorphous silicon dioxide (aSiO 2 ) occupy a very prominent place due to their abundance and fundamental and technological importance.…”

mentioning

confidence: 99%

Hydrogen-Induced Rupture of Strained Si─O Bonds in Amorphous Silicon Dioxide

et al. 2015

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Using ab initio modeling we demonstrate that H atoms can break strained Si-O bonds in continuous amorphous silicon dioxide (a-SiO2) networks, resulting in a new defect consisting of a 3-coordinated Si atom with an unpaired electron facing a hydroxyl group, adding to the density of dangling bond defects, such as E centers. The energy barriers to form this defect from interstitial H atoms range between 0.5 and 1.3 eV. This discovery of unexpected reactivity of atomic hydrogen may have significant implications for our understanding of processes in silica glass and nano-scaled silica, e.g., in porous low-permittivity insulators, and strained variants of a-SiO2.

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Imaging of the Hydrogen Subsurface Site in RutileTiO2

Cited by 87 publications

References 25 publications

Structure and diffusion of intrinsic defects, adsorbed hydrogen, and water molecules at the surface of alkali-earth fluorides calculated using density functional theory

Structure and diffusion of intrinsic defects, adsorbed hydrogen, and water molecules at the surface of alkali-earth fluorides calculated using density functional theory

Noncontact atomic force microscopy imaging of atomic structure and cation defects of the polar MgAl2O4(100) surface: Experiments and first-principles simulations

Hydrogen-Induced Rupture of Strained Si─O Bonds in Amorphous Silicon Dioxide

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