Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg_1−xCd_xTe

• Alexandra V. Galeeva,
• Alexey I. Artamkin,
• Alexey S. Kazakov,
• Sergey N. Danilov,
• Sergey A. Dvoretskiy,
• Nikolay N. Mikhailov,
• Ludmila I. Ryabova and
• Dmitry R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 1035–1039, doi:10.3762/bjnano.9.96

• . 53, 119991 Moscow, Russia 10.3762/bjnano.9.96 Abstract Terahertz photoconductivity in heterostructures based on n-type Hg1−xCdxTe epitaxial films both in the topological phase (x < 0.16, inverted band structure, zero band gap) and the trivial state (x > 0.16, normal band structure) has been studied

• 3D HgTe has been convincingly proved by ARPES experiments in several detailed studies [5][6][7]. Hg1−xCdxTe solid solutions demonstrate a composition-driven transition from the topological phase with inverted band structure to the trivial phase with normal band structure ordering at x ≈ 0.16 [8]. In

• motivated by the application aspects related to the terahertz photodetector development [12]. In our recent paper [13], we have shown that photoconductivity in Hg1−xCdxTe solid solutions at 280 µm wavelength changes its sign across the topological transition from the inverted to the normal band structure

An implementation of spin–orbit coupling for band structure calculations with Gaussian basis sets: Two-dimensional topological crystals of Sb and Bi

• Sahar Pakdel,
• Mahdi Pourfath and
• J. J. Palacios

Beilstein J. Nanotechnol. 2018, 9, 1015–1023, doi:10.3762/bjnano.9.94

• . 10.3762/bjnano.9.94 Abstract We present an implementation of spin–orbit coupling (SOC) for density functional theory band structure calculations that makes use of Gaussian basis sets. It is based on the explicit evaluation of SOC matrix elements, both the radial and angular parts. For all-electron basis

• all relevant band structure variations induced by SOC. In this work, the non-relativistic or scalar-relativistic Kohn–Sham Hamiltonian is obtained from the CRYSTAL code and the SOC term is added a posteriori. As an example, we apply this method to the Bi(111) monolayer, a paradigmatic 2D topological

• again, giving rise to the non-zero topological invariant. The essential features of the band structure of topological materials (at least the elemental ones) can be obtained from the tight-binding (TB) model where the Hamiltonian is built through a Slater–Koster [7] atomic parametrization. These models

Facile synthesis of a ZnO–BiOI p–n nano-heterojunction with excellent visible-light photocatalytic activity

• Mengyuan Zhang,
• Jiaqian Qin,
• Pengfei Yu,
• Bing Zhang,
• Mingzhen Ma,
• Xinyu Zhang and
• Riping Liu

Beilstein J. Nanotechnol. 2018, 9, 789–800, doi:10.3762/bjnano.9.72

• of ZnO/BiOI nanocomposites was greatly improved due to the p–n heterojunction structure between ZnO and BiOI. Further insight into the mechanism is illustrated as follow. Figure 7a shows the simplified energy band structure of BiOI and ZnO. The valence band maximum energies of BiOI and ZnO as

Perovskite-structured CaTiO₃ coupled with g-C₃N₄ as a heterojunction photocatalyst for organic pollutant degradation

• Ashish Kumar,
• Christian Schuerings,
• Suneel Kumar,
• Ajay Kumar and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2018, 9, 671–685, doi:10.3762/bjnano.9.62

• organic semiconductor with tri-s-triazine units, has drawn huge attention from researchers due to its excellent photocatalytic performance and unique properties such as appropriate band structure, visible light absorption and high chemical and thermal stability [2][4]. In addition, g-C3N4 consists of

• area. Moreover, these results also show that the CTCN heterojunction is not simply a physical mixture of separate CT and g-C3N4 entities [49]. Optical properties study The band gap energy of a material is directly related to its light harvesting capability. To gain insight into the band structure of

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• sites while the slow one may be related to the physical adsorption of the methanol molecules on the deficient sites. It can be assumed that the sulfur vacancies can provide active sites for gas molecules to interact with MoS2 as well as altering the position of sub-bands in the band structure [44]. The

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

• AA and AN. Another peak that has a significant intensity in graphene structures is the G′ band. The G′ band is a single peak in single-layer graphene, whereas it splits into four peaks in bilayer graphene, reflecting the evolution of the electron band structure [37][38]. However, the G′ band is not

• electronic band structure of the graphitic material. There was a decrease of the G′ peak FWHM from 117.51 cm−1 (untreated sample) to 109.51 cm−1 (treated with 80% AN and irradiated with a dose of 108 kGy) and 105 cm−1 (treated with 80% AA and irradiated with a dose of 108 kGy) (Figure 3). This happens

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

• well as on the band structure of contacting materials [86], and can be modulated by an applied source–drain bias in the on state of a NEM switch. For example, the change in the transport mechanism from direct tunnelling at low drain bias to FN tunnelling at the higher drain bias was shown for a Pd–MoS2

Transition from silicene monolayer to thin Si films on Ag(111): comparison between experimental data and Monte Carlo simulation

• Alberto Curcella,
• Romain Bernard,
• Yves Borensztein,
• Silvia Pandolfi and
• Geoffroy Prévot

Beilstein J. Nanotechnol. 2018, 9, 48–56, doi:10.3762/bjnano.9.7

• to Dirac cones near the Fermi level, have been shown to be related to a modification of the silver band structure induced by the silicene reconstruction [14][16][17][18][19]. This strong coupling also gives rise to Si–Ag atomic exchange during the deposition of Si on the Ag(111) surface [6][20][21

• successive Si layers [23][24][25][26], with an interlayer spacing of ≈3Å. Such layers display an electronic band structure, measured by ARPES, that has been interpreted as a Dirac cone located 0.25 eV below the Fermi level [27]. These layers present a metallic behavior, with an electric conductivity one

Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• energies of the N-electron systems. The DOS Dασ(ξ) of the tip and the substrate are standard quantities obtained from band-structure calculations. The calculation of the tunneling amplitudes tανσ is our main concern. We start by considering the molecule–substrate interface. The approach uses DFT to

Spin-dependent transport and functional design in organic ferromagnetic devices

• Guichao Hu,
• Shijie Xie,
• Chuankui Wang and
• Carsten Timm

Beilstein J. Nanotechnol. 2017, 8, 1919–1931, doi:10.3762/bjnano.8.192

• bias of 1.0 V. The mechanism of the multi-state MR can be understood as follows: In the present device, electrons tunnel between the Co electrodes through the OF interlayer. In the two-current model [47], and according to the band structure of Co, the electron tunneling in C1 (C2) happens between the

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

• Florian Rückerl,
• Daniel Waas,
• Bernd Büchner,
• Martin Knupfer,
• Dietrich R. T. Zahn,
• Francisc Haidu,
• Torsten Hahn and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 1601–1615, doi:10.3762/bjnano.8.160

• a clear energy gap, i.e., none of the KxMnPc phases is metallic. This, in general, resembles the situation in many molecular crystals doped with alkali metals, where it was observed that the doping did not result in a metallic ground state although metallicity would be expected on the basis of band

• -structure calculations since half-filled bands are present. Molecular crystals usually have energy bands with small band widths, which is a direct consequence of the rather small interaction between the molecules in the material. Furthermore, the bandwidth often is similar to the Coulomb repulsion of two

Comprehensive Raman study of epitaxial silicene-related phases on Ag(111)

• Dmytro Solonenko,
• Ovidiu D. Gordan,
• Guy Le Lay,
• Dietrich R. T. Zahn and
• Patrick Vogt

Beilstein J. Nanotechnol. 2017, 8, 1357–1365, doi:10.3762/bjnano.8.137

• photoemission spectroscopy measurements of this superstructure by Wang et al. [18] showed that its electronic band structure mostly comprises bands pointing to an sp3 hybridization of its Si atoms. Moreover, there are also claims that this superstructure is stabilized by Ag atoms, found either on the top or

Two-dimensional silicon and carbon monochalcogenides with the structure of phosphorene

• Dario Rocca,
• Ali Abboud,
• Ganapathy Vaitheeswaran and
• Sébastien Lebègue

Beilstein J. Nanotechnol. 2017, 8, 1338–1344, doi:10.3762/bjnano.8.135

• electronic structure that are markedly different from those of graphene, with, for instance, the existence of a finite bandgap in the band structure [5]. One of the latest newcomers in the family of two-dimensional materials is phosphorene [6][7][8][9], which corresponds to a single layer of black phosphorus

• -dimensional plane). A vacuum of at least 12 Å has been used to separate periodically repeated images. Since the PBE functional systematically underestimates the electronic gap with respect to experiments, the band structure was obtained using the HSE06 functional [29]. Because of the numerical cost involved

• in HSE06 calculations electronic eigenvalues have been computed on a 16 × 16 × 1 k-point grid; the band structure was then extracted along the high symmetry directions and interpolated with cubic splines (see below in Figure 3). Spin–orbit coupling often plays an important role in two-dimensional

ZnO nanoparticles sensitized by CuInZn_xS_2+x quantum dots as highly efficient solar light driven photocatalysts

• Florian Donat,
• Serge Corbel,
• Halima Alem,
• Steve Pontvianne,
• Lavinia Balan,
• Ghouti Medjahdi and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 1080–1093, doi:10.3762/bjnano.8.110

• relative positions of the CBs of ZCIS QDs and ZnO indicate that these materials exhibit a well-coupled band structure which should be favorable for the separation of photo-generated charge carriers and thus for photocatalytic experiments (Figure 4). Photocatalytic experiments Influence of the Orange II

• image of the ZnO/ZCIS composite. Elemental mapping of the ZnO/ZCIS composite heated at 400 °C for 15 min showing the presence of (b) Zn, (c) O, (d) Cu, (e) In and (f) S elements. High-resolution XPS spectra of (a) Zn 2p3/2 and (b) O 1s in ZnO and in the ZnO/ZCIS composite. Band structure of ZnO and ZCIS

Impact of air exposure and annealing on the chemical and electronic properties of the surface of SnO₂ nanolayers deposited by rheotaxial growth and vacuum oxidation

• Monika Kwoka and
• Maciej Krzywiecki

Beilstein J. Nanotechnol. 2017, 8, 514–521, doi:10.3762/bjnano.8.55

• with regard to SnO2-based sensing devices. It also shows that for sensor devices based on changes of the surface conductivity (resistive sensors) the oxygen uptake from ambient air is affecting the energy band structure. However, the process is reversible by de-gassing, which proves the ability of SnO2

Impact of contact resistance on the electrical properties of MoS₂ transistors at practical operating temperatures

• Filippo Giannazzo,
• Gabriele Fisichella,
• Aurora Piazza,
• Salvatore Di Franco,
• Giuseppe Greco,
• Simonpietro Agnello and
• Fabrizio Roccaforte

Beilstein J. Nanotechnol. 2017, 8, 254–263, doi:10.3762/bjnano.8.28

• band structure. As an example, MoS2 (the most studied among TMDs due to its high abundance in nature and relatively high stability under ambient conditions) exhibits an indirect bandgap of ≈1.3 eV in the case of few layers and bulk material and a direct bandgap of ≈1.8 eV in the case of a single layer

Tunable plasmons in regular planar arrays of graphene nanoribbons with armchair and zigzag-shaped edges

• Cristian Vacacela Gomez,
• Michele Pisarra,
• Mario Gravina and
• Antonello Sindona

Beilstein J. Nanotechnol. 2017, 8, 172–182, doi:10.3762/bjnano.8.18

• region is further scrutinized with a finer MP mesh of 2000 × 1 × 1 k-points, including up to 30 bands. The main results of our DFT computations are summarized in the plots of Figure 1, which show the different geometry, band structure and density of states (DOS) of the GNR arrays. 4ZGNR and 10ZGNR behave

• materials with plasmonic resonances that will be tunable to a specific demand in both the UV–vis and THz regimes, by altering the chemical doping, electronic gating, and also by means of a careful choice of the geometry. Geometry, LDA band-structure and DOS of the different (zigzag and armchair) GNR arrays

Nitrogen-doped twisted graphene grown on copper by atmospheric pressure CVD from a decane precursor

• Ivan V. Komissarov,
• Nikolai G. Kovalchuk,
• Vladimir A. Labunov,
• Ksenia V. Girel,
• Olga V. Korolik,
• Mikhail S. Tivanov,
• Algirdas Lazauskas,
• Mindaugas Andrulevičius,
• Tomas Tamulevičius,
• Viktoras Grigaliūnas,
• Šarunas Meškinis,
• Sigitas Tamulevičius and
• Serghej L. Prischepa

Beilstein J. Nanotechnol. 2017, 8, 145–158, doi:10.3762/bjnano.8.15

• layers. Many theoretical and experimental studies have focused on the unique properties of TG [4]. In particular, it was demonstrated that for angles θ > 10°, the layers are electronically decoupled, and the low-energy band structure looks like a simple superposition of the Dirac cones of the individual

Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

• Carlos. J. Páez,
• Dario. A. Bahamon,
• Ana L. C. Pereira and
• Peter. A. Schulz

Beilstein J. Nanotechnol. 2016, 7, 1983–1990, doi:10.3762/bjnano.7.189

• step from the upper zigzag edge), the resonant tunnelling permits a spectroscopy of the band structure of phosphorene nanoribbons in this energy window. Furthermore, progressive widening of the barriers (enhancing the step width of the constriction), thus nearing the constriction to the other edge

• ]. Indeed, the degeneracy comes from the fact that the width of the ribbon here is NZ = 60, which guarantees that the two edges are effectively uncoupled [24]. Hence, this width will be chosen for the host ribbon where the constriction will be introduced. The effect of edges coupling with the band structure

• by the electronic band structure discussed in the previous section raises the question of a means to observe experimentally those effective one-dimensional chains embedded in the rather complex phosphorene crystalline structure. In order to test our hypothesis we propose the segmented nanoribbon

Functionalized platinum nanoparticles with surface charge trigged by pH: synthesis, characterization and stability studies

• Giovanna Testa,
• Laura Fontana,
• Iole Venditti and
• Ilaria Fratoddi

Beilstein J. Nanotechnol. 2016, 7, 1822–1828, doi:10.3762/bjnano.7.175

• (see Figure 1), suggesting that the band structure of the Pt nanoparticles is formed [34]. After careful purification by centrifugation, the colloidal product was characterized by DLS, UV–vis spectroscopy, FTIR, and ζ-potential measurements. A FESEM study was carried out on selected samples. In Figure

Monolayer graphene/SiC Schottky barrier diodes with improved barrier height uniformity as a sensing platform for the detection of heavy metals

• Ivan Shtepliuk,
• Jens Eriksson,
• Volodymyr Khranovskyy,
• Tihomir Iakimov,
• Anita Lloyd Spetz and
• Rositsa Yakimova

Beilstein J. Nanotechnol. 2016, 7, 1800–1814, doi:10.3762/bjnano.7.173

• metals. The key issue is that the heavy metal adsorption leads to band-structure reorganization and changing of the energy gap of the graphene clusters (as was discussed before). Bandgap opening may also be expected in epitaxial monolayer graphene on SiC due to the interaction with heavy metals. It is

Graphene-enhanced plasmonic nanohole arrays for environmental sensing in aqueous samples

• Christa Genslein,
• Peter Hausler,
• Eva-Maria Kirchner,
• Rudolf Bierl,
• Antje J. Baeumner and
• Thomas Hirsch

Beilstein J. Nanotechnol. 2016, 7, 1564–1573, doi:10.3762/bjnano.7.150

• 0.58 is almost of the same order. The SPR response is affected by the presence of different plasmonic properties and accordingly strongly influenced by the dimensions of the nanostructures. A possible explanation for the findings are variations in the plasmonic band structure, leading to different

Manufacturing and investigation of physical properties of polyacrylonitrile nanofibre composites with SiO₂, TiO₂ and Bi₂O₃ nanoparticles

• Tomasz Tański,
• Wiktor Matysiak and
• Barbara Hajduk

Beilstein J. Nanotechnol. 2016, 7, 1141–1155, doi:10.3762/bjnano.7.106

• , the determined optical properties of which were similar to the properties obtained for PAN polymer fibre mats. The studies of the band structure of the obtained composite mats indicate that the best dielectric properties were of the layers made of composite PAN nanofibres reinforced with particles of

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• moieties [34]. Furthermore, certain defects also produce nanotube curvature, which in turn creates π-orbital mismatch and consequently creates more active sites on the CNT. In any case, the presence of these defects is known to affect the band structure of the carbon nanotubes and thus can be studied by

Optical absorption signature of a self-assembled dye monolayer on graphene

• Tessnim Sghaier,
• Sylvain Le Liepvre,
• Céline Fiorini,
• Ludovic Douillard and
• Fabrice Charra

Beilstein J. Nanotechnol. 2016, 7, 862–868, doi:10.3762/bjnano.7.78

• “surface only” nature [22][23] and has been applied to tailor its band structure [24] or its work function [25][26] with a monolayer of PTCDI and similar molecules, which can be laterally patterned [27] or even manipulated at the single-molecule level [28]. Beyond H-bond-steered organizations [29], a high