Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers

• Deepika Jhajhria,
• Dinesh K. Pandya and
• Sujeet Chaudhary

Beilstein J. Nanotechnol. 2018, 9, 2198–2208, doi:10.3762/bjnano.9.206

• in the magnitude and direction of both magnetization and magnetic anisotropy. It could be associated with the magnetic disorder created due to the large interfacial roughness of IrMn at higher tIrMn, which is also supported well by the XRR fitting results. On the other hand, the extrinsic

Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

• Samuel D. Escribano,
• Alfredo Levy Yeyati and
• Elsa Prada

Beilstein J. Nanotechnol. 2018, 9, 2171–2180, doi:10.3762/bjnano.9.203

• -based quantum computing devices [6][7][8][9]. Progress in fabrication techniques has allowed to induce a hard superconducting gap in InAs [10] or InSb [11] nanowires with epitaxially deposited Al layer. Moreover, last-generation devices exhibit a very low degree of disorder, which allows them to almost

• and the unavoidable presence of disorder [38]. If this is the case, it is then characterized by a finite effective dielectric permittivity which depends on the SC shell width as well as its composition, as we show in Section 1 of Supporting Information File 1. Some experiments [39] have reported that

Spin-coated planar Sb₂S₃ hybrid solar cells approaching 5% efficiency

• Pascal Kaienburg,
• Benjamin Klingebiel and
• Thomas Kirchartz

Beilstein J. Nanotechnol. 2018, 9, 2114–2124, doi:10.3762/bjnano.9.200

• -bandgap region [53][54][55][56] including band tails that yield the Urbach energy as a measure of disorder as well as the detection of (optically active) defects in the band gap which can act as recombination centers in a solar cell. The Sb-TU process shows a slight increase in uncovered substrate area

Defect formation in multiwalled carbon nanotubes under low-energy He and Ne ion irradiation

• Santhana Eswara,
• Jean-Nicolas Audinot,
• Brahime El Adib,
• Maël Guennou,
• Tom Wirtz and
• Patrick Philipp

Beilstein J. Nanotechnol. 2018, 9, 1951–1963, doi:10.3762/bjnano.9.186

• show that ion irradiation with incidence angles closer to the surface normal favours the formation of double and multiple vacancies and in-plane disorder while more grazing incidence leads mainly to single vacancies and substitution, the latter being limited to chemical species reacting with carbon [9

• in the sample. Depending on the sample a fourth peak due to intercalated graphite compounds and increasing disorder produced by functionalization and strain can appear in the region of 1617–1625 cm−1 [1]. Further information on defects can be obtained by the intensity of optical absorbance which is

• quite a large amount of disorder is present in our initial samples. For He+ irradiation at 1017 ions/cm2 two different spectra have been obtained. The spectra with D and G band has been obtained on suspended nanotubes while the spectra with only a broad G band has been recorded on a part of the sample

Synthesis of carbon nanowalls from a single-source metal-organic precursor

• André Giese,
• Sebastian Schipporeit,
• Volker Buck and
• Nicolas Wöhrl

Beilstein J. Nanotechnol. 2018, 9, 1895–1905, doi:10.3762/bjnano.9.181

• to measure the structure of the carbon bonds in the materials. In this work the method is used to determine the sp2/sp3 ratio, the disorder of the carbon structures [29][30] and to get spectroscopic fingerprints for the different structures described before. The Raman spectra in this paper are

SO₂ gas adsorption on carbon nanomaterials: a comparative study

• Deepu J. Babu,
• Divya Puthusseri,
• Frank G. Kühl,
• Sherif Okeil,
• Michael Bruns,
• Manfred Hampe and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 1782–1792, doi:10.3762/bjnano.9.169

• -graphene layers [18]. With this morphology it represents a typological carbon adsorbent with extended structural disorder. Graphene oxide (GO) has a 2D layered structure as shown schematically in Figure 1b. The starting material for the synthesis of GO is graphite, the oxidation of which introduces oxygen

• proportional to the presence of defects or disorder in the material and is strongly dependent on the laser excitation energy [32]. The 2D band for sp2-hybridized carbon materials is found between 2500 and 2800 cm−1 and is a double-resonance two-phonon process [33]. The 2D band intensity is found to be

• indicating maximum disorder in the structure. The N2 adsorption isotherms at 77 K of the six adsorbents are plotted in Figure 4a. The predominantly microporous nature of Norit R1 Extra is evident from the Langmuir-type adsorption isotherm (type I). The observed steep adsorption at low relative pressures is

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• topological invariant. These signatures are topologically robust against small perturbations, such as disorder. This means that these discontinuities and the associated zero-energy modes cannot be removed by the presence of, e.g., disorder or interactions, if these perturbations are small compared to the

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• reported below also apply to those settings. Available materials are often of sufficiently high quality to meet the conditions for ballistic transport, and we will therefore neglect disorder effects. In view of the large amount of published theoretical works on the Josephson effect in such systems, let us

Interaction-tailored organization of large-area colloidal assemblies

• Silvia Rizzato,
• Elisabetta Primiceri,
• Anna Grazia Monteduro,
• Adriano Colombelli,
• Angelo Leo,
• Maria Grazia Manera,
• Roberto Rella and
• Giuseppe Maruccio

Beilstein J. Nanotechnol. 2018, 9, 1582–1593, doi:10.3762/bjnano.9.150

• lateral capillary forces tend to induce aggregation and disorder. Nevertheless, we were able to control the surface coverage by tuning the absorption time in order to achieve a long range order. Notably, we showed how this method can be easily transferred for use with different materials to produce large

Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

• Tudor D. Stanescu,
• Anna Sitek and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1512–1526, doi:10.3762/bjnano.9.142

• topological character of these modes endows them with robustness against perturbations that do not close the superconductor gap, e.g., weak interactions, wire bending, a certain amount of disorder, etc. The most straightforward experimental signature of a Majorana mode is a zero-bias conductance peak that is

• satisfying this condition is manifest in regimes characterized by small topological gaps, as δE and ΔE become comparable in the gapless superconductor limit. Effects of disorder Another element that can compromise the topological protection of the Majorana subspace is the presence of disorder. Generically

• , disorder induces low-energy sub-gap states, thus reducing ΔE[46][47][48][49][50]. The effect of potential disorder on a topological phase realized in a triangular wire is illustrated in Figure 12. Panel (A) shows the position dependence (along the wire) of a typical disorder potential Vdis(x) considered in

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• -Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China 10.3762/bjnano.9.128 Abstract We investigate the effect of three types of intrinsic disorder, including that in pairing energy, chemical potential, and hopping amplitude, on the transport properties through the superconducting nanowires

• with Majorana bound states (MBSs). The conductance and the noise Fano factor are calculated based on a tight-binding model by adopting a non-equilibrium Green’s function method. It is found that the disorder can effectively lead to a reduction in the conductance peak spacings and significantly suppress

• the peak height. Remarkably, for a longer nanowire, the zero-bias peak could be reproduced by weak disorder for a finite Majorana energy splitting. It is interesting that the shot noise provides a signature to discriminate whether the zero-bias peak is induced by Majorana zero mode or disorder. For

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

• exhibits a clear sawtooth profile at a phase difference of π when the energy splitting is negligible, signalling a strong dependence of current–phase curves on the length of the superconducting regions. Effects of temperature, scalar disorder and reduction of normal transmission on supercurrents are also

• , therefore signalling the presence of weakly overlapping MBSs. We find that while this sawtooth profile is robust against variations in the normal transmission and scalar disorder, it smooths out when temperature effects are included, making it a fragile, yet useful, signature of MBSs. We identify that in

• of the maximum supercurrent. In particular, well-localized MBSs are revealed in the sawtooth profile of I() at = π. In what follows we analyze the effect of temperature, variation of normal transmission and random disorder on the sawtooth profile at = π of the supercurrent. Temperature effects In

Induced smectic phase in binary mixtures of twist-bend nematogens

• Anamarija Knežević,
• Irena Dokli,
• Marin Sapunar,
• Suzana Šegota,
• Ute Baumeister and
• Andreja Lesac

Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122

• intercalated smectic phase was unravelled by combined spectroscopic and computational methods and can be traced to conformational disorder of the terminal chains. These results show the importance of understanding the phase behaviour of binary mixtures, not only in targeting a wide temperature range but also

• considered to be mostly trans-planar [44]. The increase in hydrocarbon chain conformational disorder has also been intensively studied by FTIR on phospholipid bilayers and is used for monitoring of lipid hydrocarbon chain melting phase transitions [39][45][46][47]. The temperature dependent IR spectra of

• accordance with the increase of the motional rate of the molecule [37][39][41]. Considering the chemical structure of both pure compounds, it is reasonable to assume that shifting of CH2 vibrations rises from conformational disorder of terminal chains present only in the structure of BB. In order to

Electrodeposition of reduced graphene oxide with chitosan based on the coordination deposition method

• Mingyang Liu,
• Yanjun Chen,
• Chaoran Qin,
• Zheng Zhang,
• Shuai Ma,
• Xiuru Cai,
• Xueqian Li and
• Yifeng Wang

Beilstein J. Nanotechnol. 2018, 9, 1200–1210, doi:10.3762/bjnano.9.111

• intensity ratio of the D to G-band can be employed to evaluate the structure disorder of carbon materials [30][31]. Thus, the Raman spectroscopy analysis of HACC-rGO suggests that there exist some structural defects in HACC-rGO. Particularly, the resulting HACC-rGO disperses well in aqueous solutions, and

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

• disorder at the interface. Thus, the ensemble average of the tunneling amplitudes has the form: where is the length of the order of the atomic scale. The tunneling is also assumed to be independent of energy and spin and occurs locally in time and in space, i.e., from a point r on the superconducting

Thermoelectric current in topological insulator nanowires with impurities

• Sigurdur I. Erlingsson,
• Jens H. Bardarson and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1156–1161, doi:10.3762/bjnano.9.107

• = 4.0 T, for a nanowire of length L = 1000 nm. The disorder strength is set to W = 4.8 and the density of impurities is varied: ni = 3.0 nm−1, 6.0 nm−1 and 12 nm−1. For comparison, we consider two types of impurities: scalar impurities described by Equation 3 (red traces), and magnetic impurities

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

• electrons and holes. It is worth noting that the hole ground state has an s-orbital-like shape. QDs have a complicated band profile since multiple effects such as geometric confinement, strain and alloy disorder, can cause major changes in the band edges of the bulk material. It is important to know where

• to longer absorption wavelengths. In conclusion, the method presented here provides a way to incorporate the inhomogeneous environment of QDs in simulations by taking into account device geometry and quantum confinement, alloy disorder, electrostatics, many-particle interactions, and spatially

Synthesis and characterization of two new TiO₂-containing benzothiazole-based imine composites for organic device applications

• Anna Różycka,
• Agnieszka Iwan,
• Krzysztof Artur Bogdanowicz,
• Michal Filapek,
• Natalia Górska,
• Damian Pociecha,
• Marek Malinowski,
• Patryk Fryń,
• Agnieszka Hreniak,
• Jakub Rysz,
• Paweł Dąbczyński and
• Monika Marzec

Beilstein J. Nanotechnol. 2018, 9, 721–739, doi:10.3762/bjnano.9.67

• band positions shift by about 5 cm−1 for νas(CH2) and 6 cm−1 for νs(CH2) modes above the isotropisation temperature. This shows the increase of conformational disorder and mobility in hydrocarbon chains as liquid phase is formed. Figure 3b illustrates the evolution of the IR spectrum of SP2 at

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• pronounced after the transfer. For doped graphene (1.11% of nitrogen from XPS data), the D band intensity increases compared to pristine graphene, the second disorder-induced peak (the D’ band) also becomes evident, the G peak position is upshifted by ≈3 cm−1, while the 2D peak is about normal, naturally

Tuning adhesion forces between functionalized gold colloidal nanoparticles and silicon AFM tips: role of ligands and capillary forces

• Sven Oras,
• Sergei Vlassov,
• Marta Berholts,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2018, 9, 660–670, doi:10.3762/bjnano.9.61

• ligands chain length, tail group and the packing order (disorder) of the molecular coating makes functionalized NPs an attractive model systems for studying the nature of interactions, and particularly adhesion at the nano and molecular level. The prospect of modifying the chain length of the ligands

• ) self-assemble on a surface with rather a poor packing [2]. This kind of structuration leads to low density of molecules on the surface. As a result, short chains have more structural disorder and defects that promote energy dissipation through rotational and vibrational excitation modes [30]. These

Single-step process to improve the mechanical properties of carbon nanotube yarn

• Maria Cecilia Evora,
• Xinyi Lu,
• Nitilaksha Hiremath,
• Nam-Goo Kang,
• Kunlun Hong,
• Roberto Uribe,
• Gajanan Bhat and
• Jimmy Mays

Beilstein J. Nanotechnol. 2018, 9, 545–554, doi:10.3762/bjnano.9.52

• −1 and 2000 cm−1. The peaks around 1580 cm−1 and 1350 cm−1 correspond to the G band (C=C in-plane stretching mode) and D band (disorder), respectively. The D band originates from hybridized vibrational mode associated with graphene edges. It indicates the presence of some disorder in the graphene

• structure. The degree of disorder in sp2-hybridized carbon materials is given by the intensity ratio between the D band and the G band (ID/IG) [36]. This ratio is thus useful to investigate the functionalization process. The broad band around 500 cm−1 observed in the spectra of the untreated samples may be

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

• period of 4π and the interference pattern is correlated with the parity. Furthermore, this relation is still valid in the presence of moderate disorder. Figure 1b and Figure 1c are calculated for the Gaussian disorder of w = 0.06t. We can see that the relation still holds. Interestingly, when the two

• -correlated interference effect for the trivial case. Third, the maximum (minimum) value of the DOS is at = (2n + 1)π for the trivial case and at 2nπ for the nontrivial case. In Figure 1d, we show the energy spectrum as a function of the flux under strong disorder, w = 0.13t with μ = −2t + 5.7Δ. It is

• typical that the two trivial Andreev bound states are accidentally in contact with each other for the strong disorder. From Figure 1b and Figure 1d, we can see that the energy spectra are very similar between the trivial case without the MFs and the nontrivial case with the MFs. In this situation, it is

Ultralight super-hydrophobic carbon aerogels based on cellulose nanofibers/poly(vinyl alcohol)/graphene oxide (CNFs/PVA/GO) for highly effective oil–water separation

• Zhaoyang Xu,
• Huan Zhou,
• Sicong Tan,
• Xiangdong Jiang,
• Weibing Wu,
• Jiangtao Shi and
• Peng Chen

Beilstein J. Nanotechnol. 2018, 9, 508–519, doi:10.3762/bjnano.9.49

• , respectively, showing the tangential G-band at 1587 cm−1 and the disorder-induced D-band at 1347 cm−1 [31]. As is well-known, the G-band corresponds to the tangential vibration of the carbon atoms, while the D-band corresponds to unordered carbon or defective graphitic structures in a Raman spectrum for carbon

• spectrum. After the carbonization treatment (Figure 4f), all characteristic bands of the carbon aerogel are tangential G-bands and the disorder-induced D-band, which are in agreement with the SEM and FTIR results. To further confirm the reduction degree of the GO during the carbonization treatment, X-ray

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

• 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

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

• Jiajun Wang,
• Xia Liu,
• Gesmi Milcovich,
• Tzu-Yu Chen,
• Edel Durack,
• Sarah Mallen,
• Yongming Ruan,
• Xuexiang Weng and
• Sarah P. Hudson

Beilstein J. Nanotechnol. 2018, 9, 137–145, doi:10.3762/bjnano.9.16

• carbon can be clearly detected for Sa, Sb and Se. The D-band, located at 1387 cm−1, correlates to the disorder or defects in the graphitized structure (sp3-hybridized carbon), while the G-band (1540 cm−1) is assigned to the E2g mode of graphite and corresponds to the vibration of sp2-bonded carbon atoms

• in a two-dimensional hexagonal [35]. The intensity ratio of the D- to G-band (ID/IG) is a measure of the extent of disorder, and the ratio of sp3/sp2 carbon. Sa has an ID/IG ratio of 0.86, and a ratio of 1 in both Sb and Se was found. The lower ID/IG value of Sb suggests that Sb is composed of more