Intuitive human interface to a scanning tunnelling microscope: observation of parity oscillations for a single atomic chain

• Sumit Tewari,
• Jacob Bakermans,
• Christian Wagner,
• Federica Galli and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2019, 10, 337–348, doi:10.3762/bjnano.10.33

• ]. The increase in kinetic energy for the conduction electrons confined between two approaching atoms gives rise to the repulsive term [22], while the attractive interaction originates from the band structure and is found by a second-moment approximation to the tight-binding Hamiltonian [20]. From this

Two-dimensional semiconductors pave the way towards dopant-based quantum computing

• José Carlos Abadillo-Uriel,
• Belita Koiller and
• María José Calderón

Beilstein J. Nanotechnol. 2018, 9, 2668–2673, doi:10.3762/bjnano.9.249

• , defining the respective Bohr radii are a3D = a* while a2D = a*/2. The values of the effective units depend on meff and ε: Ry* = 13.6meff/ε2 eV and a* = 0.529ε/meff Å. The gap and the effective masses of different semiconducting 2D materials have been estimated from band-structure calculations [19][28

Silicene, germanene and other group IV 2D materials

• Patrick Vogt

Beilstein J. Nanotechnol. 2018, 9, 2665–2667, doi:10.3762/bjnano.9.248

• substrate can effect the buckling, which in turn, alters the properties of the 2D layer. The related modification might include, for example, the tunability of the electronic band gap, modification of the electronic band structure, or tuning the 2D topological properties. Some of these external influences

Hierarchical heterostructures of Bi₂MoO₆ microflowers decorated with Ag₂CO₃ nanoparticles for efficient visible-light-driven photocatalytic removal of toxic pollutants

• Shijie Li,
• Wei Jiang,
• Shiwei Hu,
• Yu Liu,
• Yanping Liu,
• Kaibing Xu and
• Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 2297–2305, doi:10.3762/bjnano.9.214

• ] Ag2CO3/AgBr/ZnO [42], and Ag/Ag2CO3/Bi2MoO6 [32]. The band structure of Ag2CO3 matches well with that of Bi2MoO6 [32]. Moreover, morphology modulation is another significant way to enhance photocatalytic activity. Three-dimensional nanostructures endow materials with unique physicochemical properties

• ) under visible light compared to bare Bi2MoO6 and Ag2CO3. Moreover, ACO/BMO-30 possesses good durability and stability. The enhanced photocatalytic performance is ascribed to the extended optical response and the matched band structure, reducing carrier recombination. This study offers a novel highly

Light–Matter interactions on the nanoscale

• Mohsen Rahmani and
• Chennupati Jagadish

Beilstein J. Nanotechnol. 2018, 9, 2125–2127, doi:10.3762/bjnano.9.201

• graphene with electromagnetic radiation is fascinating due to the two-dimensional confinement of electrons and the exceptional band structure of graphene. Graphene has a simple band structure with zero band gap, but its optical response is nontrivial. Subsequently, other two-dimensional (2D) materials

A scanning probe microscopy study of nanostructured TiO₂/poly(3-hexylthiophene) hybrid heterojunctions for photovoltaic applications

• Laurie Letertre,
• Roland Roche,
• Olivier Douhéret,
• Hailu G. Kassa,
• Denis Mariolle,
• Nicolas Chevalier,
• Łukasz Borowik,
• Philippe Dumas,
• Benjamin Grévin,
• Roberto Lazzaroni and
• Philippe Leclère

Beilstein J. Nanotechnol. 2018, 9, 2087–2096, doi:10.3762/bjnano.9.197

• electronic band structure of the ITO/TiO2/P3HT-COOH/tip system in short-circuit configuration. Upon illumination, the photon absorption by P3HT-COOH leads to the creation of excitons in the polymer. The electrons are transferred in the conduction band of TiO2 at the TiO2/P3HT-COOH interface. As the COOH

• ) and (f) are enlargements of images (a) and (b), respectively, corresponding to the dashed rectangle. The colour scale contrast is enhanced to highlight the main features. Schematic representation of the electronic band structure of the [TiO2/P3HT-COOH]–[tip] system, in the KPFM measurement

• ) PC-AFM height and photocurrent images of a TiO2/P3HT-COOH HHJ. The images were recorded upon calibrated illumination (AM 1.5, 100 suns), in short-circuit configuration. (e) Schematic representation of the electronic band structure of the ITO/TiO2/P3HT-COOH/tip system in short-circuit configuration

Improving the catalytic activity for hydrogen evolution of monolayered SnSe_2(1−x)S_2x by mechanical strain

• Sha Dong and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2018, 9, 1820–1827, doi:10.3762/bjnano.9.173

• functional theory (DFT) computations. The results showed SnSe2(1−x)S2x alloys with continuously changing bandgaps from 0.8 eV for SnSe2 to 1.59 eV for SnS2. The band structure of a SnSe2(1−x)S2x monolayer can be further tuned by applied compressive and tensile strain. Moreover, tensile strain provides a

• conductivity. Tuning the band structure of the catalyst is important for improving the HER efficiency. It was reported that the band structure and carrier mobility of monolayer MX2 can be tuned by substitution of M with M' atoms or X with X' atoms to form monolayer MxM'(1−x)X2 or MX2xX'2(1−x) alloys [31][32

Robust midgap states in band-inverted junctions under electric and magnetic fields

• Álvaro Díaz-Fernández,
• Natalia del Valle and
• Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

• connection between the quantum Hall effect and a topological invariant, the so-called first Chern number [2]. The fact that a quantum Hall system was insulating in the bulk but had a quantized conductivity on the edge could be related to the non-trivial topology of the band structure. In 2006, topology came

Predicting the strain-mediated topological phase transition in 3D cubic ThTaN₃

• Chunmei Zhang and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1399–1404, doi:10.3762/bjnano.9.132

• expected to substantially alter the electronic band structure and thus achieve an exotic topological property [26]. By using first-principles calculations, we demonstrate here, for the first time, that the cubic perovskite ThTaN3, a relatively large band gap semiconductor, can turn into a TI under moderate

• hybrid HSE06 functional methods, respectively. It was found that the PBE functional overestimates the experimental lattice constants by 1%, whereas the HSE06 can successfully reproduce the experimentally reported lattice parameters (4.02 Å) [2]. Figure 1 presents the detailed electronic band structure of

• gap could be significantly reduced. As shown in Figure 2a, the energy gap was reduced to 0 eV at a compressive strain of −8%. A Dirac-cone-like band structure [38] emerged with an ultrahigh Fermi velocity 6.33 × 105 m/s that is comparable to that of graphene (1.1 × 106 m/s) [39]. It is very important

The electrical conductivity of CNT/graphene composites: a new method for accelerating transmission function calculations

• Olga E. Glukhova and
• Dmitriy S. Shmygin

Beilstein J. Nanotechnol. 2018, 9, 1254–1262, doi:10.3762/bjnano.9.117

• carbon materials, namely graphene, graphane and a graphene–carbon nanotube hybrid composite. Computational Details In order to calculate the electrical conductance we use the Green–Keldysh functions and the Landauer–Büttiker formalism [8]. The calculation of energy and band structure is carried out by

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• ]. However, they did not report the band structure or the band gap values of these materials. Later, Wu et al. performed theoretical studies on silicon and germanium arsenides [9] to predict and reaffirm that m-SiAs/GeAs and o-SiAs2/GeAs2 are indeed semiconductors. The studies were based on band-structure

• the same IV–V group combination, we focus our study on two-dimensional SiAs2 and GeAs2 and compare them with their bulk counter parts with regard to electronic band structure, phonon-vibration frequencies, optical properties, band gap modulation behavior and predict their potential applications

• , respectively. To study 2D monolayer systems under periodic boundary conditions, a vacuum layer of about 15 Å was introduced to minimize the spurious interaction between neighboring layers. The electronic band structure is predicted through hybrid density functional theory based on the Heyd–Scuseria–Ernzerhof

Field-controlled ultrafast magnetization dynamics in two-dimensional nanoscale ferromagnetic antidot arrays

• Anulekha De,
• Sucheta Mondal,
• Sourav Sahoo,
• Saswati Barman,
• Yoshichika Otani,
• Rajib Kumar Mitra and
• Anjan Barman

Beilstein J. Nanotechnol. 2018, 9, 1123–1134, doi:10.3762/bjnano.9.104

• properties and magnonic band structure more efficiently due to the strong interelement exchange and dipolar coupling [28][29]. A remarkable difference in magnetic anisotropies and magnetization reversal mechanisms has been observed in systematically engineered square and binary antidot lattices [30

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

• crucial in the design and prediction of the device behavior. Therefore, this study aims to fill the gaps in current absorption models, namely the atomistic strain and band structure calculations that are needed for accurate description of the bound states. Moreover, doped devices require evaluation of

• with a thickness of 2 nm. The rest of the structure is made of Al0.07Ga0.93As. The dimensions of the simulated QD systems are 60 nm × 60 nm × 60 nm. The strain simulation contains around ten million atoms and the atomistic grid is as shown in Figure 2. The band structure calculations do not need all of

• atoms to be included in the simulation, since bound states decay exponentially outside the quantum dot. The band structure calculations are performed using a 40 nm × 40 nm × 20 nm box surrounding the quantum dot. This box contains only 1.5 million atoms. Well-defined and well-calibrated tight-binding

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