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

• separates the regimes with trivial and nontrivial topological properties of the system [3][4][18]. Further increase in the magnetic field is known to suppress the proximity effect since in the absence of the spin–orbit coupling the Fermi level crosses the only energy branch with a complete spin polarization

• 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

• standard paramagnetic effect. In contast, in the topologically nontrivial regime Tc increases (with or without initial decay at small fields). This increase in the critical temperature originates from the reduction of the proximity effect due to almost pure spin polarization of quasiparticles in the wire

Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• electrically induced reduction or oxidation may affect the degree of reduction of rGO sheets [17]. Scanning polarization force microscopy (SPFM), also called dielectric force microscopy, was developed firstly by Hu et al. in 1995 [18][19] to measure the dielectric properties of soft or weakly bound materials

• information (blue arrows marked in Figure 1i,k), indicating the contributions from the polarization force (dielectric properties) and the van der Waals force (topography) between the tip and sample. As we can see in the Figure 1l,m,n, the apparent height of samples 1 and 5 are 19.3 nm (Figure 1n) and 6.9 nm

• cantilever (Figure 3a). Because of polarization, opposing charges are induced at the vicinity of the sample surface, causing an attractive force between the tip and the sample, which leads to a phase shift of the cantilever. In the absence of electrical forces, the cantilever has a resonant frequency, f0

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

• Hana Krýsová,
• Josef Krýsa and
• Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

• photocurrent is very similar (around −0.3 V) on both our FTO supports and for various layer thicknesses. There is very small slope of the photocurrent/potential curve around the photocurrent onset and then an almost linear increase of the photocurrent. A similar shape in the polarization curve was observed

P3HT:PCBM blend films phase diagram on the base of variable-temperature spectroscopic ellipsometry

• Barbara Hajduk,
• Henryk Bednarski,
• Bożena Jarząbek,
• Henryk Janeczek and
• Paweł Nitschke

Beilstein J. Nanotechnol. 2018, 9, 1108–1115, doi:10.3762/bjnano.9.102

• polarization of reflected light. The change of light polarization is described by ellipsometric angles Ψ and Δ. Typically, ellipsometric investigations allow one to determine optical parameters, i.e., the refractive index n and the extinction coefficient k, or equivalently the complex dielectric function ε

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

• Tarek A. Ameen,
• Hesameddin Ilatikhameneh,
• Archana Tankasala,
• Yuling Hsueh,
• James Charles,
• Jim Fonseca,
• Michael Povolotskyi,
• Jun Oh Kim,
• Sanjay Krishna,
• Monica S. Allen,
• Jeffery W. Allen,
• Rajib Rahman and
• Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

• initial and final states, ń is the refractive index of the material, c is the speed of light in free space, ε0 is the free space permittivity, is the polarization of the incident light, and is the first-order dipole moment that is given by , where q is the electron charge. For transitions between bound

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• other words, the same region of the RA monolayer and graphite substrate (blue dashed line in Figure 4a) was probed in the entire image. The EFM experiment was carried out at a fixed lift height (50 nm) above the sample surface while the polarization bias Vtip was varied at finite time intervals, and a

• resulting from permanent polarization or free charges on the surface [34]. In a simpler form, Equation 1 can be rewritten as According to Equation 1 and Equation 2, and since all EFM experiments were performed using the same cantilever and at a fixed lift height (fixed capacitance geometry), ∆ω in each

• region of the image is proportional to the dielectric constant of the material underneath the EFM tip, surface potential differences and to any accumulated charges/permanent polarization at the surface [34]. Equation 2 was used to fit all experimental data in Figure 4c–e (blue or brown solid lines in

Cyclodextrin inhibits zinc corrosion by destabilizing point defect formation in the oxide layer

• Abdulrahman Altin,
• Maciej Krzywiecki,
• Adnan Sarfraz,
• Cigdem Toparli,
• Claudius Laska,
• Philipp Kerger,
• Aleksandar Zeradjanin,
• Karl J. J. Mayrhofer,
• Michael Rohwerder and
• Andreas Erbe

Beilstein J. Nanotechnol. 2018, 9, 936–944, doi:10.3762/bjnano.9.86

• , negative charge must be accumulated, either by electron accumulation or by molecular polarization. The latter is more likely, as the amount of free charge carriers in a molecular insulator such as β-CD is expected to be rather low. As the O 1s peak of β-CD is most affected by the charge dislocation, it is

• , and the nature of ZnO, however, electrons are more likely to be the dominating species. In the case of a thick oxide layer, generation of a large polarization at the interface is a further possibility. No evidence exists here for such a polarization, and it is unlikely for the investigated case with a

• thin oxide. A band bending of ca. 0.1 eV is usually observed in oxides at interfaces and also in air [39]. During corrosion processes, electrode polarization lifts the band bending to the active corrosion potential [39]. The consequence of the energy level bending makes the ZnO less an n-type

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• dielectric properties of nanomaterials, such as electrostatic force microscopy [16][17][18][19], scanning polarization force microscopy (SPFM) [20][21][22][23], local dielectric spectroscopy [24][25][26], and nanoscale capacitance microscopy [27][28][29]. Most of the proposed techniques are based on long

• , Fadh, will increase due to sample polarization (Figure 1b), which is positively correlated to its dielectric constant. Therefore, adhesion force mapping under a biased AFM tip can be expected to characterize the local dielectric property distribution. An example of adhesion force mapping with a biased

• substrate. This result indicates the increase in the adhesion force when the AFM tip is biased is due to the greater degree of polarization of CRGO with respect to the mica substrate, rather than charge injection into the CRGO sheets [43]. In this case, the apparent height of the CRGO sheet under the biased

Effect of ferroelectric BaTiO₃ particles on the threshold voltage of a smectic A liquid crystal

• Abbas R. Imamaliyev,
• Mahammadali A. Ramazanov and
• Shirkhan A. Humbatov

Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76

• -decyloxybenzoate and 4-cyano-4′-pentylbiphenyl with a molar ratio of 1:1. The mixture is in the smectic A phase in the temperature range of 32.5–47.0 °C and has positive dielectric anisotropy. BaTiO3 is a ferroelectric material with high spontaneous polarization (0.26 C·m−2 at room temperature) [16][17]. In our

• . Ferroelectric particles have a dipole moment due to residual polarization and in the absence of a field their dipole moments are oriented parallel to the LC molecules (polarization–director coupling [23]). When an electric field is applied, these dipoles rotate to oriente themselves in the direction of the

• Figure 3) is associated with a slowing of the ratio P/E when the polarization approaches saturation. According to the formula this leads to a decrease in the dielectric permittivity of the particles and the colloid as a whole. This is confirmed by similar measurements in the crystalline phase of the

Valley-selective directional emission from a transition-metal dichalcogenide monolayer mediated by a plasmonic nanoantenna

• Haitao Chen,
• Mingkai Liu,
• Lei Xu and
• Dragomir N. Neshev

Beilstein J. Nanotechnol. 2018, 9, 780–788, doi:10.3762/bjnano.9.71

• 10.3762/bjnano.9.71 Abstract Background: Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) with intrinsically crystal inversion-symmetry breaking have shown many advanced optical properties. In particular, the valley polarization in 2D TMDCs that can be addressed optically has inspired new

• polarization; Introduction The inversion-symmetry breaking and quantum confinement in monolayer TMDCs offer unprecedented opportunities to explore valley-based physics and applications [1][2][3]. The valley pseudospin is associated with the degenerate energy extrema in momentum space [3]. In monolayer TMDCs

• [6][7][8][9][10]. In particular, monolayer TMDCs with direct bandgap at the K and K′ points [11] make it possible to control the valley degree freedom entirely optically. Optical pumping of excitons of a specific valley polarization has been demonstrated by polarization-resolved photoluminescence (PL

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

• Kaliappan Muthukumar,
• Harald O. Jeschke and
• Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

• energy cut-off of 400 eV was used and all ions were fully relaxed using a conjugate gradient scheme until the forces were less than 0.01 eV/Å. In the geometry optimizations for the molecule and the surface models the Brillouin zone was sampled at the Γ point only. Spin polarization was considered for all

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• the visible spectrum was promoted through LSPR and is very well ascribed to the electric polarization effect. Moreover, LSPR also speeds up the electron movement from the photoexcited noble metal to the semiconductor [5]. The morphology, interparticle interactions and the local dielectric environment

High-contrast and reversible scattering switching via hybrid metal-dielectric metasurfaces

• Jonathan Ward,
• Khosro Zangeneh Kamali,
• Lei Xu,
• Guoquan Zhang,
• Andrey E. Miroshnichenko and
• Mohsen Rahmani

Beilstein J. Nanotechnol. 2018, 9, 460–467, doi:10.3762/bjnano.9.44

• ; Introduction Metasurfaces are thin and flat surfaces that are created using subwavelength optical antennas with various optical properties patterned at interfaces [1][2], enabling control over the polarization, phase, amplitude, and dispersion of light. Metasurfaces are growing in popularity as their optical

• properties can be adapted to a diverse set of applications along the electromagnetic spectrum [3] including dispersion engineering [4], polarization manipulation [5][6], pulse shaping [7], sensing [8][9] and tuning [10]. The first generation of metasurfaces mostly consisted of plasmonic nanostructures [11

• , respectively. The polarization of the incident beam is along y direction (along the gold bar lengths). A grating resonance in the spectrum occurs around 1235 nm at the grating diffraction edge (λ0 = n × D = 1.45 × 850 nm = 1232.5 nm) due to the constructive diffractive feedback among neighbouring antennas

Engineering of oriented carbon nanotubes in composite materials

• Razieh Beigmoradi,
• Abdolreza Samimi and
• Davod Mohebbi-Kalhori

Beilstein J. Nanotechnol. 2018, 9, 415–435, doi:10.3762/bjnano.9.41

• hard, solid or powder, biological, and organic or inorganic surfaces. This device can measure geometric morphology, adhesion distribution, friction, surface impurities, texture, elasticity, magnetism, chemical bonding forces, distribution of electric charges and electric polarization in different parts

• mode (G-band), disorder-induced mode (D-band), and other Raman features, determining the physical properties of the material. The G-band intensity as a function of the angle of polarization for individual CNTs can be related to their arrangement so that the G-band intensity of well-aligned CNT bulk

• materials should be higher than that of less-aligned CNTs. Figure 22 shows field emission (FE)-SEM micrographs of two CNT samples with random and aligned orientation and their polarized Raman spectra at 0° and 90° (0° related to the polarization direction of the laser light where it is parallel to the CNT

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• ], the polarization field around a spherical cavity inside a dielectric medium is proportional to the applied field, so: Inside an anisotropic dielectric (the liquid crystal) the spherical cavity changes into an ellipsoid with the semi-axes and , where b is the cavity radius, is the parallel

• permittivity, is the perpendicular permittivity. In this case H becomes: where d(z) the depolarization coefficient, which for an ellipsoid with almost spherical shape (horizontal axis equal b = R and vertical axis a = R + 0.0005R) is If a quantum dot is placed inside this cavity, another polarization field

• was checked by using polarization microscopy. The mass concentration was 0.89%, which led to a volumetric fraction of 1.16% (the QD density is 0.87 g/cm3 and the density of 5CB is 1.02 g/cm3). The mixture was used to fill a 15 μm thick planar aligned cell from Instek, which was mounted in a holder

Design of polar self-assembling lactic acid derivatives possessing submicrometre helical pitch

• Alexej Bubnov,
• Cyril Vacek,
• Michał Czerwiński,
• Terezia Vojtylová,
• Wiktor Piecek and
• Věra Hamplová

Beilstein J. Nanotechnol. 2018, 9, 333–341, doi:10.3762/bjnano.9.33

• easily reachable by applying of a low frequency a.c. electric field. Spontaneous quantities The temperature dependences of the spontaneous polarization Ps and of the tilt angle θs (angle of (in-layer) molecular director with respect to the smectic layer normal) are shown in Figure 2a,b, respectively. The

• values of the spontaneous polarization Ps do not reveal any tendency to saturate on cooling. While comparing the homologues with the same length of non-chiral terminal chain, the Ps as well as θs values were found to slightly decrease with the increasing length of the alkyl chain at the chiral carbon

• ) for KL3/4 (a) and KL 4/5 (b). Vertical arrows indicate the peaks corresponding to phase transitions. Temperature dependencies of spontaneous polarization Ps, (a) and tilt angle of molecules θs, measured optically (b) for KL 3/4 (black rectangle), KL 3/5 (red circle), KL 4/4 (green triangle), KL 4/5

Synthesis and characterization of electrospun molybdenum dioxide–carbon nanofibers as sulfur matrix additives for rechargeable lithium–sulfur battery applications

• Ruiyuan Zhuang,
• Shanshan Yao,
• Maoxiang Jing,
• Xiangqian Shen,
• Jun Xiang,
• Tianbao Li,
• Kesong Xiao and
• Shibiao Qin

Beilstein J. Nanotechnol. 2018, 9, 262–270, doi:10.3762/bjnano.9.28

• the selected voltage region. Additionally, when comparing the CV of the pure sulfur electrode, a distinguishable positive shift in the reduction–oxidation peaks of the sulfur/MoO2–CNF composites can be observed, which confirms a relatively low potential polarization with MoO2–CNF additives. An

Dielectric properties of a bisimidazolium salt with dodecyl sulfate anion doped with carbon nanotubes

• Doina Manaila Maximean,
• Viorel Cîrcu and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 164–174, doi:10.3762/bjnano.9.19

• functions. As a result of doping the ILC with CNT, the electric conductivity increases significantly. Ionic conductivity is dominant and it was indirectly observed through the electrode polarization (EP) effect. The very high dielectric permittivity values and the decrease of the electric conductivity at

• constant temperatures. An increase of the conductivity with CNT concentration and temperature is also observed as presented in Figure 12. Ionic conductibility Two major polarizing mechanisms can be studied by means of DS: a) polarization due to orientation of permanent molecular electrical dipoles and b

• ) polarization due to the movement of mobile charge carriers. Due to the presence of mobile charge carriers in LCs, a supplementary induced polarization needs to be considered when interpreting experimental data, namely the electrode polarization, resulting from charge accumulation at the electrode/sample

Atomic layer deposition and properties of ZrO₂/Fe₂O₃ thin films

• Kristjan Kalam,
• Helina Seemen,
• Peeter Ritslaid,
• Mihkel Rähn,
• Aile Tamm,
• Kaupo Kukli,
• Aarne Kasikov,
• Joosep Link,
• Raivo Stern,
• Salvador Dueñas,
• Helena Castán and
• Héctor García

Beilstein J. Nanotechnol. 2018, 9, 119–128, doi:10.3762/bjnano.9.14

• thin films was investigated. Additionally, the influence of composition and structure on electrical and magnetic properties was studied. Several samples exhibited a measurable saturation magnetization and most of the samples exhibited a charge polarization. Both phenomena were observed in the sample

• film and TiN electrode layer is distinguishable; the film is dense and the crystal growth has started immediately together with the nucleation process. The TEM image proves the formation of a stacked layer structure. Electrical and magnetic properties Most samples exhibited charge polarization, as

• shown in Figure 6. Charge polarization was found to decrease as the amount of Fe2O3 in the films increased (Figure 6). The charge polarization–applied voltage loops, in principle, look similar to those observed earlier for materials grown by ALD and targeted as ferroelectrics, such as LiNbO3 [36][37

Design of photonic microcavities in hexagonal boron nitride

• Sejeong Kim,
• Milos Toth and
• Igor Aharonovich

Beilstein J. Nanotechnol. 2018, 9, 102–108, doi:10.3762/bjnano.9.12

• dashed line (y-axis) shown in the inset (i.e., along the width of the 1D PCC). The dipole emitter in the simulation is y-polarized to match the polarization of the optical mode. The Purcell enhancement has a maximum in the center of the nanobeam where the electric field intensity is the greatest. The

Nematic liquid crystal alignment on subwavelength metal gratings

• Irina V. Kasyanova,
• Artur R. Geivandov,
• Vladimir V. Artemov,
• Maxim V. Gorkunov and
• Serguei P. Palto

Beilstein J. Nanotechnol. 2018, 9, 42–47, doi:10.3762/bjnano.9.6

• a liquid crystal into a hybrid system is especially interesting as it can result in even more novel and interesting properties. In our recent work, we showed that liquid crystals strongly affect both the plasmon resonance and light polarization properties of subwavelength metal gratings [9

• the input polarization (Figure 3d), on the contrary, gratings are bright and gratings and the reference squares are dark. Such a behavior proves that the LC director above the gratings is aligned in the plane formed by the sample axis and the normal to the gratings, whereas above the gratings, a

• polarization is rotated by the twisted LC layer, which does not allow independent measurements of the TE and TM-mode spectra. Conclusion We have demonstrated that the subwavelength aluminum nanogratings can be used to align nematic liquid crystal material with its easy axis along the slits. In order to study

Electro-optical characteristics of a liquid crystal cell with graphene electrodes

• Nune H. Hakobyan,
• Hakob L. Margaryan,
• Valeri K. Abrahamyan,
• Vladimir M. Aroutiounian,
• Arpi S. Dilanchian Gharghani,
• Amalya B. Kostanyan,
• Timothy D. Wilkinson and
• Nelson Tabirian

Beilstein J. Nanotechnol. 2017, 8, 2802–2806, doi:10.3762/bjnano.8.279

• of a photodetector. When the He–Ne laser beam (632 nm) propagates through the LC cell placed between crossed polarizers (so that the direction of the polarization of the incident beam makes a 45° angle with the LC director), then the influence of an external electric field allows typical oscillations

Ab initio study of adsorption and diffusion of lithium on transition metal dichalcogenide monolayers

• Xiaoli Sun and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2017, 8, 2711–2718, doi:10.3762/bjnano.8.270

• represented as double zeta basis sets plus polarization, and a cut-off energy of 250 Ry was chosen to calculate the Hamiltonian element. The Monkhorst–Pack scheme with 11 × 11 × 1 k-point meshes were used for integration in the irreducible Brillouin zone for the relaxation of the primitive cell. A 2 × 2 × 1 k

Inelastic electron tunneling spectroscopy of difurylethene-based photochromic single-molecule junctions

• Youngsang Kim,
• Safa G. Bahoosh,
• Dmytro Sysoiev,
• Thomas Huhn,
• Fabian Pauly and
• Elke Scheer

Beilstein J. Nanotechnol. 2017, 8, 2606–2614, doi:10.3762/bjnano.8.261

• quality with polarization functions on all non-hydrogen atoms [20]. To model charge transport through the junctions, either the open or closed form of the C5F-ThM molecule was connected to two Au clusters of 53 atoms to the left and the right side of the molecule, as shown in Figure 2a. The clusters

• functionals, as used here, tends to underestimate the HOMO–LUMO gaps of molecules and does not capture nonlocal surface polarization effects that are essential for an accurate description of metal–molecule level alignments, we use here the so-called DFT+Σ method [34][35]. By adding a self-energy correction

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• effects such as electrical polarisation and backflow. Because magnetic fields do not lead to polarization and exhibit an increased stability (low backflow) they can be a suitable alternative for these devices. There are two major reason why magnetic fields are not used in phase modulation. The first

• a laser beam (Figure 1) they produce an intensity variation: where Δφ = 2πl/λ is the phase difference between ordinary and extraordinary ray. Figure 1 shows a schematic representation of this system. The polarizer axis is at a 45° angle αp relative to the polarization axis of incident laser beam