Design aspects of Bi₂Sr₂CaCu₂O_8+δ THz sources: optimization of thermal and radiative properties

• Mikhail M. Krasnov,
• Natalia D. Novikova,
• Roger Cattaneo,
• Alexey A. Kalenyuk and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 1392–1403, doi:10.3762/bjnano.12.103

• mesa size, as well as whisker and electrode widths are λ1/8 = 37.5 μm; the crystal height is λ1/10 = 30 μm; mesa and whisker heights and the electrode thickness are λ1/100 = 3 μm; the simulation sphere radius is R = 2λ1 and the perfectly matching layer thickness is 0.2λ1. The sizes and parameters are

• mesa. The same color scale is used, indicated in the middle panel of Figure 6b. The rightmost panels represent far-field radiation patterns (directionality diagrams) of the electric field amplitude outside the simulation sphere. From comparison of the middle panels in Figure 6a,b it can be seen that

• device. Left panels show sketches of devices; middle panels – electric field amplitudes in the x-z cross-section through the mesa; right panels represent radiation patterns for the electric field amplitude in the far-field (outside the simulation sphere). Note a strong field concentration between the

Cantilever signature of tip detachment during contact resonance AFM

• Devin Kalafut,
• Ryan Wagner,
• Maria Jose Cadena,
• Anil Bajaj and
• Arvind Raman

Beilstein J. Nanotechnol. 2021, 12, 1286–1296, doi:10.3762/bjnano.12.96

• photodiode amplitude signal in units of μrad to a numerical simulation of the cantilever response driven by moment couples of different magnitudes. Figure 1c shows the maximum deflection of the cantilever about static equilibrium for the numerical simulations. The dashed grey line in this Figure indicates

• measurements. We also explore the aggregate numerical simulation data of Figure 1 by way of the phase space representation in Figure 3. The phase space has as many dimensions as state variables, but we restrict our viewing to the dominant contributors of the first three basis function modal coordinates

• Figure 1, the system was simulated at a selected bending moment couple drive amplitude until steady-state, at which point the frequency was stepped incrementally up or down using final state variable values from the previous simulation point as initial conditions. A fast Fourier transform of the steady

Nonmonotonous temperature dependence of Shapiro steps in YBCO grain boundary junctions

• Leonid S. Revin,
• Dmitriy V. Masterov,
• Alexey E. Parafin,
• Sergey A. Pavlov and
• Andrey L. Pankratov

Beilstein J. Nanotechnol. 2021, 12, 1279–1285, doi:10.3762/bjnano.12.95

• at low temperatures. Nevertheless, the simulation qualitatively follows the experimental dependence within the entire temperature range. The obtained effect of the optimum in the JJ response is associated with a simultaneous change of several parameters when the temperature changes. For a qualitative

A review on slip boundary conditions at the nanoscale: recent development and applications

• Ruifei Wang,
• Jin Chai,
• Bobo Luo,
• Xiong Liu,
• Jianting Zhang,
• Min Wu,
• Mingdan Wei and
• Zhuanyue Ma

Beilstein J. Nanotechnol. 2021, 12, 1237–1251, doi:10.3762/bjnano.12.91

• force [39][40][41][42]. However, compared with experimental methods, numerical simulations, such as the lattice Boltzmann method and molecular dynamics (MD) simulation, are more attractive in many aspects. First, numerical simulations can readily reach the system sizes and timescales of practical

• interaction energy, and water slippage (or friction coefficient) may also not have a one-to-one correspondence between each other [67][68][69]. Contrary to the conventional wisdom, where slip boundary conditions are not valied for water slippage on hydrophilic surfaces, some simulation observations show that

• length correspondingly decreases [23][46]. Joly et al. proposed an approximate model to describe the relationship between the slip length and surface charge density. They validated the model by using a MD simulation with an ionized solution system represented by models of ideal solvents and ions [46

The effect of cobalt on morphology, structure, and ORR activity of electrospun carbon fibre mats in aqueous alkaline environments

• Markus Gehring,
• Tobias Kutsch,
• Osmane Camara,
• Alexandre Merlen,
• Hermann Tempel,
• Hans Kungl and
• Rüdiger-A. Eichel

Beilstein J. Nanotechnol. 2021, 12, 1173–1186, doi:10.3762/bjnano.12.87

• further improved by applying a copper tape connecting the sample and the graphite tape. To identify the particles decorating the nanofibres, EDX was performed using an Octane Super EDX detector (EDAX). The programme “monte CArlo SImulation of electroN trajectory in sOlids” (CASINO) [23], which simulates

Irradiation-driven molecular dynamics simulation of the FEBID process for Pt(PF₃)₄

• Alexey Prosvetov,
• Alexey V. Verkhovtsev,
• Gennady Sushko and
• Andrey V. Solov’yov

Beilstein J. Nanotechnol. 2021, 12, 1151–1172, doi:10.3762/bjnano.12.86

• presents a detailed computational protocol for the atomistic simulation of formation and growth of metal-containing nanostructures during focused electron beam-induced deposition (FEBID). The protocol is based upon irradiation-driven molecular dynamics (IDMD), a novel and general methodology for computer

• . The methodology can also be adjusted to simulate the nanostructure formation by other nanofabrication techniques using electron beams, such as direct electron beam lithography. In the present study, the methodology is applied to the IDMD simulation of the FEBID of Pt(PF3)4, a widely studied precursor

• nanostructures. The analysis of the simulation results provides spatially resolved relative metal content, height, and growth rate of the deposits, which represents valuable reference data for the experimental characterization of the nanostructures grown by FEBID. Keywords: focused electron beam-induced

Criteria ruling particle agglomeration

• Dieter Vollath

Beilstein J. Nanotechnol. 2021, 12, 1093–1100, doi:10.3762/bjnano.12.81

• of an agglomerated ensemble, that is, an exponential function characterized by two parameters. In this context, it is important to realize that one has to take care of fluctuations of the entropy. Keywords: agglomeration; enthalpy; entropy; simulation; surface energy; van der Waals interaction

• must not be exceeded. It is necessary to distinguish between the entropy fluctuation phenomenon described by Mishin and that explained earlier by Crooks [16] for small systems. Results Results of the entropy simulation As described in the previous chapter, the maximum entropy principle gives clear

• , together with the evaluation of the simulation calculations are given in Table 1. To improve readability, in this table, instead of ncoll the parameter a = ncoll/Ntot is given. This table compares the results obtained from Equation 11 and from simulations. As fluctuation processes influence the simulation

A new method for obtaining model-free viscoelastic material properties from atomic force microscopy experiments using discrete integral transform techniques

• Berkin Uluutku,
• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2021, 12, 1063–1077, doi:10.3762/bjnano.12.79

• single Voigt unit in series with a spring. Details about the simulation and the material parameters can be found in the Methods section. Linear ramp stress is applied to the material, from which the corresponding strain is calculated. This calculation gives the stress vs strain as a time-dependent array

• illustrated in Figure 5 for the data provided in Figure 4. Furthermore, although we have used a viscoelastic model to generate the material behavior for our simulation, the calculated retardance and relaxance (Figure 4 and Figure 5) are directly derived from the response of the material and are model-free

• simulation provides a fair approximation according to Figure 6. As the value of z increases along the real axis, the value of the retardance approaches the theoretical glassy compliance, which refers to the material’s infinitely short-timescale response (i.e., instantaneous response), and which is

Is the Ne operation of the helium ion microscope suitable for electron backscatter diffraction sample preparation?

• Annalena Wolff

Beilstein J. Nanotechnol. 2021, 12, 965–983, doi:10.3762/bjnano.12.73

• concentration and would be sufficiently high to form a Cu3Ga phase. This value represents an average and does not take random elements of the Ga distribution into account. The simulation results suggest that phase transformations are not likely to occur homogeneously throughout the sample but rather are

• the steady-state condition is reached later, allowing for a higher Ga impurity implantation concentration. The experimental result is in good agreement with the theoretical prediction from the Monte Carlo simulation and subsequent calculations. The Cu3Ga phase-transformed regions are larger for the

• SRIM simulation suggested that each copper atom is displaced around 22 times during the polishing process. A high enough Cu atom as well as Ga ion mobility is likely to move ions as well as displaced Cu atoms into grain boundaries. Grain boundaries can facilitate transport deeper into the material and

In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures

• Olena M. Kapran,
• Roman Morari,
• Taras Golod,
• Evgenii A. Borodianskyi,
• Vladimir Boian,
• Andrei Prepelita,
• Nikolay Klenov,
• Anatoli S. Sidorenko and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 913–923, doi:10.3762/bjnano.12.68

• by SQUID magnetometry in a field parallel to the film in the normal state at T > Tc. A significant hysteresis of M(H) reveals the in-plane anisotropy of Co films (albeit with a small coercive field, HC ≈ 30 Oe), consistent with earlier studies [44][45][46][47]. Figure 1c shows a numerical simulation

Effects of temperature and repeat layer spacing on mechanical properties of graphene/polycrystalline copper nanolaminated composites under shear loading

• Chia-Wei Huang,
• Man-Ping Chang and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2021, 12, 863–877, doi:10.3762/bjnano.12.65

• construction of the simulation models. Different sizes of the model were tested to find the optimal size for good simulations at minimal computational time and to determine if finite-size effects arise from the model dimensions. A size of 10 nm × 10 nm × 22 nm of the model was found acceptable. The average

• interactions between C and Cu atoms are calculated by Lennard-Jones (LJ) potentials, using parameters of 0.019996 eV and 3.225 Å [35]. The simulation system uses an isothermal–isobaric (NPT) ensemble to reach equilibrium by a Nose–Hoover thermostat for 100000 time steps. The shear loading is performed by

• applying a consistent velocity to the composites along the x-direction. The grain size D of the simulation model ranges from 4.24 to 9.43 nm. Deformation and dislocation evolution of the model are analyzed and visualized using the Open Visualization Tool (OVITO). Results and Discussion Effect of

Reducing molecular simulation time for AFM images based on super-resolution methods

• Zhipeng Dou,
• Jianqiang Qian,
• Yingzi Li,
• Rui Lin,
• Jianhai Wang,
• Peng Cheng and
• Zeyu Xu

Beilstein J. Nanotechnol. 2021, 12, 775–785, doi:10.3762/bjnano.12.61

• resolution. Theoretical investigations are getting highly important for the interpretation of AFM images. Researchers have used molecular simulation to examine the AFM imaging mechanism. With a recent flurry of researches applying machine learning to AFM, AFM images obtained from molecular simulation have

• also been used as training data. However, the simulation is incredibly time consuming. In this paper, we apply super-resolution methods, including compressed sensing and deep learning methods, to reconstruct simulated images and to reduce simulation time. Several molecular simulation energy maps under

• different conditions are presented to demonstrate the performance of reconstruction algorithms. Through the analysis of reconstructed results, we find that both presented algorithms could complete the reconstruction with good quality and greatly reduce simulation time. Moreover, the super-resolution methods

Recent progress in actuation technologies of micro/nanorobots

• Ke Xu and
• Bing Liu

Beilstein J. Nanotechnol. 2021, 12, 756–765, doi:10.3762/bjnano.12.59

• electromagnetic fields in the application of micro/nanorobots, used finite element methods to simulate the magnetic field generated by a coil assembly in order to actuate micro/nanorobots more effectively. At the same time, a three-dimensional magnetic simulation was carried out to reveal the magnitude of the

• magnetic force on a cylindrical micro/nanorobot. Via experimental measurements, the simulation results were verified and the validity of the simulation was proved. The results of this research provide reference values for the application of electromagnetically actuated micro/nanorobots. Introducing

Prediction of Co and Ru nanocluster morphology on 2D MoS₂ from interaction energies

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2021, 12, 704–724, doi:10.3762/bjnano.12.56

• Ab initio Simulation Package (VASP) version 5.4 [49]. Three-dimensional boundary conditions were applied and the spin-polarized general gradient approximation (GGA) along with the Perdew–Burke–Ernzerhof (PBE) approximation to the exchange–correlation functional were used to describe the system [50

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

Determining amplitude and tilt of a lateral force microscopy sensor

• Oliver Gretz,
• Alfred J. Weymouth,
• Thomas Holzmann,
• Korbinian Pürckhauer and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2021, 12, 517–524, doi:10.3762/bjnano.12.42

• for a given amplitude and tilt. Finally, the amplitude and tilt are determined by fitting the simulation output to the data with oscillation. Keywords: frequency-modulation atomic force microscopy; lateral force microscopy; amplitude calibration; tilt estimation; Introduction Frequency-modulation

• amplitude. In this paper we present a method to calibrate the amplitude and determine the tilt of the LFM sensor. The method is based on collecting STM data of a surface feature both without and with tip oscillation, as was proposed in [20]. The data without oscillation is used as input to a simulation that

Simulation of gas sensing with a triboelectric nanogenerator

• Kaiqin Zhao,
• Hua Gan,
• Huan Li,
• Ziyu Liu and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2021, 12, 507–516, doi:10.3762/bjnano.12.41

• simulation, we measured the potential difference between the outer surfaces of the two dielectric materials as ds is gradually increased from 0.1 to 1 mm, as shown in Figure 3c, which also reflects the influence of the distance between the two triboelectric materials on the potential. In practice, it is

• driven by the potential difference between the two sides. Figure 5e,f shows the electric potential in the simulation of rectangle, isosceles triangle, and right-angled triangle. The electric potentials obtained for the three models are basically the same, but it can be found that the electric potential

• materials approach or move away from each other, other substances, such as water vapor, carbon dioxide, and other gases, can pass through the gap. We present a simulation with water vapor under ideal conditions, that is, the surface charge density may be changed during the experiment. A simplified two

Surface-enhanced Raman scattering of water in aqueous dispersions of silver nanoparticles

• Paulina Filipczak,
• Krzysztof Hałagan,
• Jacek Ulański and
• Marcin Kozanecki

Beilstein J. Nanotechnol. 2021, 12, 497–506, doi:10.3762/bjnano.12.40

• average size of 34 ± 14 nm. The temperature experiment results showed a higher enhancement with temperature increase. Performed simulation studies revealed a slowdown of the mobility of the water molecules close to the surface of AgNPs. Keywords: Dynamic lattice liquid (DLL) simulations; liquid water

• metal surfaces, which is very different in comparison to bulk water [24]. It was explained that the ordering of water molecules near to AgNPs is due to the electrostatic interactions between water and AgNPs. Some simulation studies also reported the enhancement of hydrogen bonds in the water structure

• AgNPs. Therefore, one can simply conclude that more energy is needed to destroy the water structure in the AgNPs dispersion than in pure water. Simulation studies Dynamic lattice liquid (DLL) simulation studies based on the face-centred cubic (FCC) lattice approach were performed, in which averaged

Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene

• Zhao Liu,
• Antoine Hinaut,
• Stefan Peeters,
• Sebastian Scherb,
• Ernst Meyer,
• Maria Clelia Righi and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2021, 12, 432–439, doi:10.3762/bjnano.12.35

• energies of the K+ (Br−) ions on Ir, an energy difference equivalent to the one shown in Equation 1 was performed, where the total energy of the isolated K (Br) atoms was considered instead of EKBr. To calculate the partial charges on the atoms in the simulation cells, the Bader method was chosen [43][44

• a triple-atom duplication along “BBC”) indicated in (a), respectively. DFT simulation of a monolayer KBr on Ir(111). (a) Optimization of a reconstructed KBr layer on Ir(111) with a cell size of 4 × 2 superimposed on the Ir(111) model and experimental data (Br− in red and K+ in blue, the size of the

Scanning transmission helium ion microscopy on carbon nanomembranes

• Daniel Emmrich,
• Annalena Wolff,
• Nikolaus Meyerbröker,
• Jörg K. N. Lindner,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2021, 12, 222–231, doi:10.3762/bjnano.12.18

• simulation was run with 50,000 ions at energies of either 15 or 30 keV. The CNM was approximated as a carbon layer with a thickness between 0.3 and 13 nm. From the SRIM output file of all transmitted ions, an angular distribution was generated (see Figure 3a). The simulation results, obtained for different

• between 3 nm thin and 1.5 nm thin CNMs for different acceptance angles. While the difference in the signal is low at small and large angles, the simulation results show that it reaches a maximum at an acceptance angle of 10 mrad. Depending on the acceptance angle of the detector, maximum brightness or

• maximum contrast between different thicknesses are adjustable. The simulation results suggest that smaller acceptance angles are ideal for applications where brightness is important, such as end-point detection for, for example, nanopores. Especially on extremely thin membranes such as CNMs, milling

Determination of elastic moduli of elastic–plastic microspherical materials using nanoindentation simulation without mechanical polishing

• Hongzhou Li and
• Jialian Chen

Beilstein J. Nanotechnol. 2021, 12, 213–221, doi:10.3762/bjnano.12.17

• depends on the indentation depth. It demonstrates that nanoindentation on microspherical materials exhibits a “size effect”. Keywords: elastic–plastic; microsphere; nanoindentation; Oliver–Pharr method; simulation; Introduction Instrumented nanoindentation is the most commonly used technique for the

• finite element method [14][15][16][17][18][19][20][21][22][23][24][25]. Using finite element simulation, Li et al. found that both loading curve and unloading curve at any depth can be generated from one indentation depth by scaling P ∝ h2 for the indentation tests of PMMA thin films with a Berkovich

• a vertical displacement on the rigid conical indenter. The contact between the indenter and the microsphere was frictionless. The calculation steps of nanoindentation simulation can be described as follows [1][2]: Construct an axisymmetric model of a microsphere and generate its finite element mesh

Mapping the local dielectric constant of a biological nanostructured system

• Wescley Walison Valeriano,
• Rodrigo Ribeiro Andrade,
• Juan Pablo Vasco,
• Angelo Malachias,
• Bernardo Ruegger Almeida Neves,
• Paulo Sergio Soares Guimarães and
• Wagner Nunes Rodrigues

Beilstein J. Nanotechnol. 2021, 12, 139–150, doi:10.3762/bjnano.12.11

• optical reflectance measurements and simulation, we were able to describe the origin of the strongly iridescent wing colors of this Amazonian rainforest damselfly. The method we demonstrate here should be useful for the study of other biological nanostructured systems. Keywords: dielectric constant

• reliable since there is a direct relation between the relative permittivity and the refractive index. Figure 8 shows the results of the simulation. On the left panels, the profile of the refraction index used to fit the optical reflectance are shown for each color region of the wing. As explained above

• correspond to the nanometric layers that constitute the wing. The dielectric constant of the peaks ranges between 8 and 9, and that of the valleys between 5 and 6. The red shadow on the black lines shows the standard deviation. Panels on the left show the refractive index profile used in the simulation and

Numerical analysis of vibration modes of a qPlus sensor with a long tip

• Kebei Chen,
• Zhenghui Liu,
• Yuchen Xie,
• Chunyu Zhang,
• Gengzhao Xu,
• Wentao Song and
• Ke Xu

Beilstein J. Nanotechnol. 2021, 12, 82–92, doi:10.3762/bjnano.12.7

• optimal tip size can be derived from the simulation results. Methods Model and parameters The model in the simulation is based on an MS1V-T1K-type quartz tuning fork used in our experiment (details will be described later). The dimensions of the MS1V-T1K quartz tuning fork, length L = 3423 µm, width W

• . The epoxy glue is defined as a cuboid in order to facilitate mesh generation and reduce calculation time, since it is not guaranteed to have a fixed geometry after curing. The glue thickness in the simulation is set to be the average glue thickness of the qPlus sensor used in our experiment. In this

• case, the volume of the glue in the simulation is approximately equal to the volume of the glue in the experiment. Figure 2d is a false-color representation of the total displacement levels. Warmer colors represent a larger displacement. All calculations were carried out using COMSOL Multiphysics

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

• Yuri Ya. Gafner,
• Svetlana L. Gafner,
• Darya A. Ryzkova and
• Andrey V. Nomoev

Beilstein J. Nanotechnol. 2021, 12, 72–81, doi:10.3762/bjnano.12.6

• composition; however, the size of the resulting particles varies significantly. To solve this issue, we studied the formation of Cu–Au nanoparticles with different chemical compositions from a gaseous medium using computer molecular dynamics (MD) simulation. The aim was to determine the effect of the

• MD simulation, it was concluded that an increase in the percentage of gold atoms in the initial vapor phase led to a decrease in the size of the synthesized nanoparticles. In addition, it was found that clusters with a size of more than 400–500 atoms, regardless of the chemical composition of the

• initial vapor phase, basically corresponded to a given target composition. Keywords: binary nanoparticles; computer simulation; copper; gold; molecular dynamics; Introduction The nanometer-sized Cu–Au compounds are being studied quite actively [1][2][3][4][5][6][7][8] because of their potential

Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes

• Saja Al-Khabouri,
• Salim Al-Harthi,
• Toru Maekawa,
• Mohamed E. Elzain,
• Ashraf Al-Hinai,
• Ahmed D. Al-Rawas,
• Abbsher M. Gismelseed,
• Ali A. Yousif and
• Myo Tay Zar Myint

Beilstein J. Nanotechnol. 2020, 11, 1891–1904, doi:10.3762/bjnano.11.170

• , illustrated in the simulation of the O 1s peak in Figure 8e, can be assigned to three distinct oxygen species. The main peak at 530.1 eV corresponds to the crystal lattice oxygen O2−. The peak at 531.5 eV can be attributed to adsorbed molecular oxygen [24] and the third peak at 533.1 eV is common for C=O [44