| 1. |
- Aref, Thomas, 1980, et al.
(författare)
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Quantum Acoustics with Surface Acoustic Waves
- 2016
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Ingår i: Superconducting Devices in Quantum Optics. - Cham : Springer International Publishing. - 9783319240916 ; , s. 217-244
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- It has recently been demonstrated that surface acoustic waves (SAWs) can interact with superconducting qubits at the quantum level. SAW resonators in the GHz frequency range have also been found to have low loss at temperatures compatible with superconducting quantum circuits. These advances open up new possibilities to use the phonon degree of freedom to carry quantum information. In this chapter, we give a description of the basic SAW components needed to develop quantum circuits, where propagating or localized SAW-phonons are used both to study basic physics and to manipulate quantum information. Using phonons instead of photons offers new possibilities which make these quantum acoustic circuits very interesting. We discuss general considerations for SAW experiments at the quantum level and describe experiments both with SAW resonators and with interaction between SAWs and a qubit. We also discuss several potential future developments.
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| 2. |
- Kjellander, Roland, 1948
(författare)
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Electrostatics in Electrolytes Expressed in an Exact Formalism Reminiscent of the Poisson–Boltzmann Picture
- 2014
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Ingår i: Electrostatics of Soft and Disordered Matter. - Singapore : Pan Stanford Publishing. - 9789814411851 ; , s. 51-67 Chapter 5
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Bokkapitel (refereegranskat)abstract
- In the PB approximation for electrolyte systems one assumes that the solvent behaves like a dielectric continuum and that the charge of each ion interacts with the average electrostatic potential from other ions in the system, neglecting the correlations. In reality an ion does not "feel" the mean potential since the ions and the solvent molecules in its neighborhood correlate with it—each ion has a local "ion and solvent cloud" of its own where the ion distribution deviate from the average one and where the locations and orientations of solvent molecules are affected. This cloud affects the interactions felt by the ion. In this treatise it is shown how it is possible to include such effects in an exact manner for the screened electrostatic interactions. Thereby, the exact theory of electrolyte solutions with discrete solvent molecules is reformulated in a manner that has a similar structure as the PB approximation theory. The screened electrostatic interaction between any two particles in the system is then written in terms of the average electrostatic potential due to one of them interacting with an effective charge distribution of the other (rather than with the bare charges as assumed in the PB approximation). This effective charge distribution also has the role as the source of the average electrostatic potential when the latter is expressed in terms of the screened rather than the ordinary (unscreened) Coulomb potential. The resulting exact formalism maintains a large part of the physical transparency of the PB theory. A major conceptual advantage is that the formalism separates out the screened electrostatics among complex consequences of the various interactions.
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| 3. |
- Krasnok, A. E., et al.
(författare)
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All-Dielectric Nanophotonics: Fundamentals, Fabrication, and Applications
- 2018
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Ingår i: World Scientific Series in Nanoscience and Nanotechnology. - : World Scientific. - 2301-301X .- 2335-6693. ; , s. 337-385
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter reviews a novel, rapidly developing field of modern light science named all-dielectric nanophotonics. This branch of nanophotonics is based on the properties of high-index dielectric nanoparticles which allow for controlling both magnetic and electric responses of a nanostructured matter. Here, we discuss optical properties of high-index dielectric nanoparticles, methods of their fabrication, and recent advances in practical applications, including the quantum source emission engineering, Fano resonances in all-dielectric nanoclusters, surface enhanced spectroscopy and sensing, coupled-resonator optical waveguides, metamaterials and metasurfaces, and nonlinear nanophotonics.
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| 4. |
- Li, Gang, et al.
(författare)
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Quantum Spin Hall States in 2D Bismuth-Based Materials
- 2019
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Ingår i: Springer Series in Materials Science. - Singapore : Springer Singapore. - 2196-2812 .- 0933-033X. ; , s. 351-379
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Berrys phase, an inherent constituent of the electronic wave functions, has revolutionarily enriched our understanding of the fundamental states of matter and has triggered the discovery of many interesting phenomena in condensed matter physics, such as quantum charge/spin pumping, polarization, topological insulating phase, etc. Among them, the discovery of the two-dimensional (2D) quantum spin Hall (QSH) states protected by time-reversal symmetry (TRS) boosts the wide interest in the study of topological materials in the past decade. These include the 2D quantum anomalous Hall states (QAH), three-dimensional topological insulators (TIs), Dirac semimetals (SM), and topological nodal-line SMs as well as Weyl SMs. This article by no means can cover everything of this rapidly developing field, we rather focus on the bismuth-based honeycomb materials hosting large-gap QSH/QAH states, which promise applications for room-temperature spintronic. We will explain their topological mechanisms in terms of Berrys phase and topological invariant. After introducing a concrete material example which has been successfully grown in experiment, e.g., Bi/SiC(0001), various theoretical proposals on atom substitution and functionalization based on bismuth honeycomb lattice will then be discussed, from which a general designing principle for achieving large topological gaps can be summarized. This article hopes to stimulate more experimental activities toward the examination of large-gap QSH/QAH theoretical proposals and the potential applications in spintronic devices.
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| 5. |
- Popok, Vladimir, 1966
(författare)
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Energetic cluster-surface collisions
- 2010
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Ingår i: Handbook of nanophysics, Vol. 2 Clusters and Fullerenes (edited by Klaus D. Sattler). - New York : Taylor&Francis. - 9781420075557
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Bonetti, Stefano, et al.
(författare)
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Nano-Contact Spin-Torque Oscillators as Magnonic Building Blocks
- 2013
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Ingår i: Magnonics. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642302466 ; , s. 177-187, s. kapitel 13 s 177-187
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Bokkapitel (refereegranskat)abstract
- We describe the possibility of using nano-contact spin-torque oscillators (NC-STOs) as fundamental magnonic building blocks. NC-STOs can act as spin wave generators, manipulators, and detectors, and can hence realize all the fundamental functions necessary for fully integrated magnonic devices, which can be fabricated using available CMOS compatible large-scale spin-torque device production processes. We show in particular how a 200 nm sized nano-contact located on an out-of-plane magnetized permalloy "free" magnetic layer can generate spin waves at f approximate to 15 GHz that propagate up to 4 mu m away from the nano-contact with wavelength lambda = 200-300 nm, decay length lambda(r) approximate to 2 mu m and group velocities v(g) approximate to 3 mu m/ns. We propose that the same type of NC-STOs can be used as spin wave manipulators, via control of the local Gilbert damping, and as spin wave detector using the spin torque diode effect.
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| 7. |
- Kesarimangalam, Sriram, 1983, et al.
(författare)
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Fluorescence Microscopy of Nanochannel-Confined DNA
- 2024
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Ingår i: Methods in Molecular Biology. - 1940-6029 .- 1064-3745. - 9781071633779 - 9781071633762 ; , s. 175-202
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Stretching of DNA in nanoscale confinement allows for several important studies. The genetic contents of the DNA can be visualized on the single DNA molecule level, and the polymer physics of confined DNA and also DNA/protein and other DNA/DNA-binding molecule interactions can be explored. This chapter describes the basic steps to fabricate the nanostructures, perform the experiments, and analyze the data.
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| 8. |
- Monemar, Bo, et al.
(författare)
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Nanowire-Based Visible Light Emitters, Present Status and Outlook
- 2016
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Ingår i: Semiconductor Nanowires : Properties and Applications - Properties and Applications. - : Elsevier. - 0080-8784. - 9780128040164 ; 94, s. 227-271
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Bokkapitel (refereegranskat)abstract
- So far, the semiconductor nanowire research area has mainly delivered results on growth procedures and related material properties. As the development lately has been successful in producing novel nanowire-based structures for optical or electronic applications, the time is ripe to review the device work that has been done and in some cases has produced devices ready for the market. In this chapter, we shall review the specific area of nanowire-based LEDs (NW-LEDs) for visible light, including the application area of “solid state lighting” (SSL). A brief review of the progress in the area of visible light LEDs over the last half century is presented, this also mentions some of the progress made in the planar technology so far. The most successful way of producing white light is still based on the use of phosphors, just like in the present compact fluorescence lamps (CFLs). The reason for this is the high efficiency (external quantum efficiency > 80%) possible at low currents in the violet planar InGaN-based LEDs used to excite the phosphors. These LEDs are presently mainly produced on foreign substrates, leading to a high dislocation density (DD) and a sizeable droop at high injection currents (25–40%). This droop and the down conversion energy loss in the phosphors (20–25%) has motivated the interest for a phosphor-less white light source based on direct mixing of light of different wavelength (such as red, green, and blue; RGB). To be competitive, this solution must be based on highly efficient LEDs for all RGB (red, green, and blue) colors. Since NW-LED structures can be produced basically free of structural defects (even if grown on a foreign substrate), the idea of using the RGB mixing concept for the production of white light sources with an ultimately higher efficiency than for the phosphor-based lamps is a major technical target for a second generation of light sources in the SSL field. Basic concepts behind the design and optical properties of NW-LED structures are discussed in this chapter, with emphasis on the present developments of III-nitride-based structures. The growth procedure relevant for such NW-LED structures is reported in some detail, specifically the core–shell configuration readily produced with metalorganic vapor phase epitaxy (MOVPE). The first generation processing technology for NW-LED structures is briefly described; this is naturally quite different from the established routines for planar LED chips. Experimental data for nitride-based NW-LEDs for blue, green, and even longer wavelengths are given in terms of radiative efficiencies, light outcoupling, droop, and long-term reliability. The experience so far is that for these NW-based emitters, efficiencies can be obtained that are close to those for the corresponding planar LEDs. There are still problems with the reproducibility of the radiative output, as well as a significant droop that would not be expected for m-plane emitters. More work is needed to pinpoint the cause of these problems. Finally, we briefly discuss various applications (also other than white lamps) where the NW-LEDs may have a specific advantage.
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| 9. |
- Moth-Poulsen, Kasper, 1978
(författare)
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Preface
- 2016
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Ingår i: Handbook of Single-Molecule Electronics. - 9789814463393 ; , s. xiii-xiv
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Since the first visionary publications about the concepts of singlemolecule electronics came out about 40 years ago, the research field has evolved into a truly interdisciplinary effort attracting contributors from various disciplines such as synthetic chemistry, theoretical chemistry and physics, experimental physics, and electronic engineering. Although great progress in both experimental realizations and theoretical understanding of single-molecule devices has been made, making it possible (to some extent) to predict and design molecular electronic components with tailored properties is still a challenge and still many steps are to be taken to overcome them before we will see widespread use of computing devices based on single molecules.
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| 10. |
- Schröder, Elsebeth, 1966, et al.
(författare)
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The vdW-DF Family of Non-Local Exchange-Correlation Functionals
- 2017
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Ingår i: Non-covalent Interactions in Quantum Chemistry and Physics: Theory and Applications. ; , s. Chapter 8-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- van der Waals interactions are a phenomenon where charge fluctuations in one part of a system correlate with fluctuations in another, resulting in an attractive force. Such interactions are thus a truly non-local correlation effect. While the full—albeit unknown—density functional does include these interactions, standard local and semi-local density functionals cannot account for these non-local effects by construction and yield qualitatively erroneous predictions. The simplest expression of a non-local functional of the density rho(r) takes the formIntegral[d3r d3r' rho(r) phi(r,r') rho(r')], but it was not until the end of the last century that the means to find a physically motivated, general, and transferable kernel rho emerged. The present chapter discusses the work on this kernel rho leading to the development of the successful van der Waals density functional (vdW-DF) and its variants.
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