Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states

• Jorge Cayao,
• Annica M. Black-Schaffer,
• Elsa Prada and
• Ramón Aguado

Beilstein J. Nanotechnol. 2018, 9, 1339–1357, doi:10.3762/bjnano.9.127

• the order parameter is assumed to be zero as it is only relevant when investigating Andreev bound states in SNS junctions. In Figure 2 we present the low-energy spectrum for a superconducting nanowire as a function of the Zeeman field at a fixed wire length LS. Figure 2a shows the case of zero

Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds

• Yuri P. Panarin,
• Sithara P. Sreenilayam,
• Jagdish K. Vij,
• Anne Lehmann and
• Carsten Tschierske

Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121

• around the long axes needs to be broken by aligning one of the short axes or if the long axes need to be subjected to such a strong magnetic field. Can such a large field induce the orientational order parameter greater than its thermodynamic value? Nevertheless it is now clear that many of the

Inverse proximity effect in semiconductor Majorana nanowires

• Alexander A. Kopasov,
• Ivan M. Khaymovich and
• Alexander S. Mel'nikov

Beilstein J. Nanotechnol. 2018, 9, 1184–1193, doi:10.3762/bjnano.9.109

• interest in these systems is stimulated by the perspectives of their use for design of topologically protected quantum bits. The key idea is based on the observation that for a certain range of parameters and rather strong applied magnetic fields H the induced superconducting order parameter reveals so

• along the magnetic field direction. The nonzero spin–orbit coupling destroys this spin polarization mixing different spin projections and resulting in a nonzero induced superconducting gap in the wire of approximately αΔind/gβH, where Δind is the induced superconducting order parameter in the wire, and

• α is the spin–orbit coupling constant. Still, even in the presence of the spin–orbit coupling the increasing magnetic field suppresses the induced superconductivity, which definitely restores the superconducting order parameter in the S film. This reentrant superconductivity stimulated by the

Optical orientation of nematic liquid crystal droplets via photoisomerization of an azodendrimer dopant

• Sergey A. Shvetsov,
• Alexander V. Emelyanenko,
• Natalia I. Boiko,
• Alexander S. Zolot'ko,
• Yan-Song Zhang,
• Jui-Hsiang Liu and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 870–879, doi:10.3762/bjnano.9.81

• of dendrimer molecules in the nematic matrix is considered. We elaborate a method for estimation of the orientational order parameter of the azobenzene fragments in a nematic matrix at different percentages of isomers. Results and Discussion Orientational structure modulation in NLC droplets NLC

• dendrimer moieties do not penetrate into glycerol due to their hydrophobic properties. Under light irradiation, the azobenzene fragments partially transform into the bent cis isomers having a very small order parameter in the nematic matrix [40]. In the case of azobenzene monomers (M), the order parameter

• of the cis isomers, Scis, equals ca. 0.1, which is much smaller than the order parameter of the nematic matrix. In our case, Scis should be further reduced by the disturbance of dendrimer molecular branches, and thus, can be neglected. In the environment of disordered cis isomers, the trans isomers

Revealing the interference effect of Majorana fermions in a topological Josephson junction

• Jie Liu,
• Tiantian Yu and
• Juntao Song

Beilstein J. Nanotechnol. 2018, 9, 520–529, doi:10.3762/bjnano.9.50

• wave function of the hole part, which is the self-Hermitian property of the MF. Thus, the general wave function of the MFs should be [42]: Here, is the wave function of the electron part, when the phase of the superconducting order parameter is 0. In the Top-JJ shown in Figure 1(a), and These two

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• enable essentially bulk-like uniform nematic ordering in the central part of a system. This effect is reminiscent of the Faraday cavity phenomenon in electrostatics. We observe that in certain confinement geometries, varying the correlation length size of the order parameter could trigger a global

• components [10]: an amplitude (also referred to as a hydrodynamic) field, and a symmetry breaking (also referred to as a gauge or nonhydrodynamic) field. If the characteristic size of a nanoparticle is comparable to the amplitude correlation length of an order parameter (which roughly estimates the core size

• confinement and/or an external electric field on topological defects in a nematic liquid crystal. We use the Landau–de Gennes approach [5] in terms of the tensor order parameter . In its eigenframe it is expressed as , where and λi are the corresponding eigenvectors and eigenvalues, respectively. We consider

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

• Agata Siarkowska,
• Miłosz Chychłowski,
• Daniel Budaszewski,
• Bartłomiej Jankiewicz,
• Bartosz Bartosewicz and
• Tomasz R. Woliński

Beilstein J. Nanotechnol. 2017, 8, 2790–2801, doi:10.3762/bjnano.8.278

• ], the reaction of an LC–NP composite to the electric field is related to the order parameter. The reduction of the order parameter can be confirmed by two effects observed during our experiments. The first one is the lowering of the threshold voltage presented in Table 2 and the second is the reduction

• of the nematic–isotropic phase transition temperature visible in Figures 7–11. Both of these effects indicate that the reduction of the elastic constant occurs as well as the reduction of the order parameter (as the elastic constant is proportional to the square of the order parameter). This is also

Beyond Moore’s technologies: operation principles of a superconductor alternative

• Igor I. Soloviev,
• Nikolay V. Klenov,
• Sergey V. Bakurskiy,
• Mikhail Yu. Kupriyanov,
• Alexander L. Gudkov and
• Anatoli S. Sidorenko

Beilstein J. Nanotechnol. 2017, 8, 2689–2710, doi:10.3762/bjnano.8.269

• parameter phases, δθ. The superconducting order parameter corresponds to the wave function of superconducting electrons |ψ|eiθ in the Ginzburg–Landau theory [17]. The magnetic flux Φ in a superconducting loop of inductance L provides an increase of the superconducting phase along the loop and results in a

• is the superconducting order parameter phase difference across the Josephson junction. It is called the Josephson phase. By presenting the relation between the superconducting order parameter phase and the magnetic flux as φ = 2πΦ/Φ0, we note that CPR couples current with the magnetic flux in a

• interactions in superconducting circuits. The absence of resistance (R = 0) leads to the absence of voltage (V = 0) in a superconducting circuit in stationary state. Superconducting current flow does not correspond to a difference of electrical potential (V = δ) but to the difference of superconducting order

Stick–slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

• Iakov A. Lyashenko,
• Vadym N. Borysiuk and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2017, 8, 1889–1896, doi:10.3762/bjnano.8.189

• the stick–slip mode of boundary friction. An analytical description and numerical simulation with radial distributions of the order parameter, stress and strain were performed to investigate the spatial inhomogeneity. It is shown that in the case when the driving device is connected to the upper part

• relevant physical results. The dependence of the order parameter on elastic strain in the lubricant layer, obtained using the above-mentioned thermodynamic approach, agrees with the similar data obtained from computational studies [14][15][16]. Moreover, strain–stress curves obtained in [10] are confirmed

• positive constants. The order parameter φ is a periodic component of the microscopic density of the material: in a solid-like state of the lubricant φ > 0, while in a liquid-like state φ = 0. Using Equation 1 and the definition τ = ∂f / ∂εel [10][22] shear stresses that appear in the lubricant can be

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

• Benedikt W. Stolz,
• Daniel D. Tune and
• Benjamin S. Flavel

Beilstein J. Nanotechnol. 2016, 7, 1486–1491, doi:10.3762/bjnano.7.141

• photovoltaic performance of devices produced with and without dry shear aligning is compared. Keywords: absorbance; carbon nanotubes; current-voltage; dry shear aligning; order parameter; Introduction During the last decade or so, the potential benefits of using carbon nanotubes in solar cells has been

• absorbance spectra were unchanged by DSA however, Figure 2b shows the variation in the degree of alignment of the nanotubes in the films after DSA, where the 2D order parameter is calculated from polarised optical transmittance measurements as in Equation 1 [44] and reveals that the degree of alignment

• surface of the films using the newly developed technique of dry shear aligning. Whilst the DSA process produced films that were two orders of magnitude flatter and exhibited a 2D order parameter of up to 0.3, both of which have been previously observed to improve the photovoltaic performance of carbon

Three-gradient regular solution model for simple liquids wetting complex surface topologies

• Sabine Akerboom,
• Marleen Kamperman and
• Frans A. M. Leermakers

Beilstein J. Nanotechnol. 2016, 7, 1377–1396, doi:10.3762/bjnano.7.129

• the critical value. Introducing an order parameter φ = φ – 0.5, we can write F as a function of the order parameter and then Taylor series expand the logarithms up to the fourth order in the order parameter. As a result we obtain a Landau free energy in terms of the order parameter. An Euler–Lagrange

Plasticity of nanocrystalline alloys with chemical order: on the strength and ductility of nanocrystalline Ni–Fe

• Jonathan Schäfer and
• Karsten Albe

Beilstein J. Nanotechnol. 2013, 4, 542–553, doi:10.3762/bjnano.4.63

• choose different values for Δμ to chemically equilibrate the system at a global composition, deviating from the stoichiometric concentration. The short range order in the system was evaluated by computing the Warren and Cowley [24] order parameter for each atom surrounded by its 12 nearest neighbors as

Size-dependent phase diagrams of metallic alloys: A Monte Carlo simulation study on order–disorder transitions in Pt–Rh nanoparticles

• Johan Pohl,
• Christian Stahl and
• Karsten Albe

Beilstein J. Nanotechnol. 2012, 3, 1–11, doi:10.3762/bjnano.3.1

• transition (lmn = [222] and [400]), are shown in the plots. In both plots we look at the concentration-averaged order parameter . At 50 atom % platinum a transition can still be observed in the short-range order parameters at around 218 K for the 7.8 nm particle even though the ordered 40-phase in the core

• shown that in the case of a bulk material it does not matter whether the parameter is centered at an A or a B atom, i.e., However, for finite systems with a surface, generally , as was discussed by Atasanov and Hou recently [31]. They also suggested the use of a concentration-averaged short-range order

• parameter as a more suitable measure for the order in the core of the particles. In this paper, we use both definitions of the order parameters in order to obtain the maximum amount of information about the system. Another approach to probe ordering transitions in particles is to use the conventional

Magnetic interactions between nanoparticles

• Steen Mørup,
• Mikkel Fougt Hansen and
• Cathrine Frandsen

Beilstein J. Nanotechnol. 2010, 1, 182–190, doi:10.3762/bjnano.1.22

• temperature dependence of the order parameter can be calculated by use of Boltzmann statistics [35][40] where E(θ) is given by Equation 9. Equation 11 can be solved numerically to estimate the temperature dependence of the order parameter. If the relaxation is fast compared to the timescale of Mössbauer

• comparing with the theoretical superferromagnetism model (Equation 11) [35][40]. Figure 6 shows the temperature dependence of the order parameter, b50(T) of the 50% quantile of the hyperfine field distribution (the median hyperfine field) for interacting 20 nm hematite nanoparticles. The solid line is a fit

• to the superferromagnetism model (Equation 11). The order parameter vanishes at T0 ≈ 390 K, where the particles become superparamagnetic. For comparison, the Néel temperature of bulk hematite is about 955 K. The strength of interactions between nanoparticles is very sensitive to the method of sample

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• Pt segregation is probably overcompensated by the energy needed to form Fe3Pt from FePt. 2.4 Structure of FePt nanoparticles Since the magnetic hardness of FePt alloys strongly depends on the chemical order parameter, we investigated the structure of individual particles by aberration corrected HRTEM