NMR study of Li adsorbed on the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mn>111</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mtext>−</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>3</mml:mn><mml:mo>×</mml:mo><mml:mn>1</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mtext>−</mml:mtext><mml:mi mathvariant="normal">Li</mml:mi></mml:mrow></mml:math>surface

Bromberger, C.; Jänsch, H.J.; Kühlert, O.; Schillinger, R.; Fick, D.

doi:10.1103/physrevb.69.245424

Cited by 9 publications

(6 citation statements)

References 55 publications

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“…For adsorption on doped semiconductor surfaces it is possible to produce at least theoretically temperature independent relaxation rates in the saturation regime. 18 To our knowledge this has never been observed experimentally on surfaces yet. But it is well known that the saturation regime can only be reached with a changing Fermi level position.…”

Section: Discussionmentioning

confidence: 86%

“…In contrast to our previous publications 12,18,38 DOS͑E͒ denotes now the electron density of states for one spin direction only. ͉⌽ F ͑0͉͒ 2 denotes the probability to find at E F an electron at the nucleus.…”

Section: A Schematic Modelmentioning

confidence: 82%

“…45,46 Heating was available by electron bombardment from the rear, cooling by contact to a liquid helium reservoir, instead of a LN 2 one as in previous experiments. 12,18,38 The lowest temperature reached at the Si crystal was 50 K.…”

Section: Experimental Technique and Setupmentioning

confidence: 99%

“…10,11,14,15 This is supported by the fact that for other reconstructions of the Si͑111͒-surface, as the Si͑111͒-͑3 ϫ 1͒ : Li, Si͑111͒-͑1 ϫ 1͒ : H, SiC͑111͒-͑3 ϫ 3͒, etc., correlation effects seem to modify substantially the single particle ͑electron͒ picture as well. 4,[15][16][17][18] The geometric and energetic properties of the ͑7 ϫ 7͒-reconstruction are well described within the DimerAdatom-Stackingfault ͑DAS͒ model. 6,[19][20][21][22] It leaves 19 dbs of the original 49 ones, one of the corner hole atom, 6 of the rest atoms, and 12 of the adatoms.…”

Section: Introductionmentioning

confidence: 99%

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MetallicSi(111)−(7×7)-reconstruction: A surface close to a Mott-Hubbard metal-insulator transition

et al. 2005

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Li adsorption at extremely low coverages ͑10 −3 ML and below͒ on the metallic Si͑111͒-͑7 ϫ 7͒ surface has been studied by ␤-NMR experiments ͑measurement of T 1 -times͒. Instead of increasing linearly with the sample temperature, as expected for a metallic system, the relaxation rate ␣ =1/T 1 is almost constant in between 50 K and 300 K sample temperature and rises considerably above. Comparison with T 1 -times around 900 K ͑ob-served with 6 Li-NMR͒ excludes adsorbate diffusion as the cause of the relaxation rate. Thus the almost temperature independent relaxation rate below 300 K points to an extremely localized and thus narrow band ͑width about 10 meV͒ which pins the Fermi energy. It is responsible for the metallicity of the ͑7 ϫ 7͒-reconstruction. Because of the steeply rising relaxation rate beyond 300 K this narrow band is located energetically within a gap ͑approximately 100-500 meV wide͒ in between a lower filled and an upper empty ͑Hubbard͒ band. Due to its extremely narrow width it can hardly be detected in photo electron experiments. In dynamical mean field theories based on Hubbard Hamiltonians this kind of density of states is typical for correlated electron systems close to a Mott-Hubbard metal-insulator transition.

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Section: Discussionmentioning

confidence: 86%

Section: A Schematic Modelmentioning

confidence: 82%

Section: Experimental Technique and Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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MetallicSi(111)−(7×7)-reconstruction: A surface close to a Mott-Hubbard metal-insulator transition

et al. 2005

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“…In principle, detection of defects can be done either indirectly, through their effect on the physical/electrical properties of the semiconductor, or directly by 3D structural imaging. The physical/electrical activity of the defects can be detected and characterized by techniques such as ESR, [111][112][113][114][115] NMR, [116][117][118] deep level transient spectroscopy, [119][120][121] and thermally stimulated current. 122,123 For large enough samples, these types of measurements can be used to detect even low densities of electrically active defects (introducing levels in the forbidden energy gap).…”

Section: Esr Nanoscopymentioning

confidence: 99%

ESR Microscopy and Nanoscopy with “Induction” Detection

Blank

Freed

2006

Israel Journal of Chemistry

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The current state‐of‐the‐art in the fields of Nuclear Magnetic Resonance (NMR) and Electron Spin Resonance (ESR) micro‐imaging is reviewed. Special attention is given to the uniqueness and the advantages of the conventional “induction” detection method with respect to other emerging sensitive magnetic resonance detection and imaging techniques. Following this, a theoretical description of the factors affecting the sensitivity and resolution in induction detection ESR is provided. Based on the theory, new approaches to substantially improve ESR capabilities, both at room temperature and at low cryogenic temperatures, are discussed. Representative results of experiments conducted at room temperature and at frequencies of 10–16 GHz show that with test samples, a sensitivity of ∼107 electron spins and a resolution of ∼3 microns are currently available. The results confirm the validity of the theoretical approach and confirm the value of striving for even higher frequencies and lower temperatures, in order to further improve the performance Finally, some of the current and potential applications of ESR microscopy and nanoscopy (involving imaging with a resolution of ∼100 nm or better) are presented.

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Solid-State NMR of Inorganic Semiconductors

Yesinowski

2011

Topics in Current Chemistry

104

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Studies of inorganic semiconductors by solid-state NMR vary widely in terms of the nature of the samples investigated, the techniques employed to observe the NMR signal, and the types of information obtained. Compared with the NMR of diamagnetic non-semiconducting substances, important differences often result from the presence of electron or hole carriers that are the hallmark of semiconductors, and whose theoretical interpretation can be involved. This review aims to provide a broad perspective on the topic for the non-expert by providing: (1) a basic introduction to semiconductor physical concepts relevant to NMR, including common crystal structures and the various methods of making samples; (2) discussions of the NMR spin Hamiltonian, details of some of the NMR techniques and strategies used to make measurements and theoretically predict NMR parameters, and examples of how each of the terms in the Hamiltonian has provided useful information in bulk semiconductors; (3) a discussion of the additional considerations needed to interpret the NMR of nanoscale semiconductors, with selected examples. The area of semiconductor NMR is being revitalized by this interest in nanoscale semiconductors, the great improvements in NMR detection sensitivity and resolution that have occurred, and the current interest in optical pumping and spintronics-related studies. Promising directions for future research will be noted throughout.

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NMR study of Li adsorbed on theSi(111)−(3×1)−Lisurface

Cited by 9 publications

References 55 publications

MetallicSi(111)−(7×7)-reconstruction: A surface close to a Mott-Hubbard metal-insulator transition

MetallicSi(111)−(7×7)-reconstruction: A surface close to a Mott-Hubbard metal-insulator transition

ESR Microscopy and Nanoscopy with “Induction” Detection

Solid-State NMR of Inorganic Semiconductors

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