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

• sources. In this work we analyze thermal and radiative properties of such devices based on mesa structures of a layered high-temperature superconductor Bi2Sr2CaCu2O8+δ. Two types of devices are considered containing either a conventional large single crystal or a whisker. We perform numerical simulations

• needle-like whisker. We present numerical simulations for various geometrical configurations and parameters and make a comparison with experimental data. It is demonstrated that the structure and the geometry of both the superconductor and the electrodes play important roles. Electrodes provide an

• Comsol Multiphysics. Below, we present simulations of thermal and radiative properties calculated using “Heat Transfer” and “RF” modules, respectively. The presented simulations contain several simplifications and, therefore, are not aiming to self-consistently predict the extent of self-heating, ΔT, or

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

• to improve their measurements. We shed light on this issue by deliberately pushing both our experimental equipment and numerical simulations to the point of tip–sample detachment to explore cantilever dynamics during a useful and observable threshold feature in the measured response. Numerical

• simulations of the analytical model allow for extended insight into cantilever dynamics such as full-length deflection and slope behavior, which can be challenging or unobtainable in a standard equipment configuration. With such tools, we are able to determine the cantilever motion during detachment and

• nonlinear response feature to the onset of tip–sample detachment in our numerical simulations to confirm the conclusions from prior works [26][27][28]. The simulations allow for deeper insight into cantilever dynamics during the interaction between the AFM probe tip and the sample, which in turn allow us to

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

• shown in Figure 1. Figure 2 shows the IVCs for temperatures of 70 and 50 K in the absence of a high-frequency signal and in the regime of detecting external 72 or 265 GHz signals. The measurement results are in good agreement with the numerical simulations (the black curves). It should be noted that the

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

• conversion from 3 to 70% [23]. Generally, the methods to investigate slip boundary conditions for nanoconfined liquids include theoretical analysis, physical experiments, and numerical simulations [8][24][25][26][27][28][29][30][31][32][33][34]. In recent years, machine learning methods have also been

• 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

• nanoflows [43]. Additionally, numerical methods can provide a controllable way to change a certain property of liquid or solid walls while other properties remain unchanged [44]. In comparison with physical experiments, numerical simulations allow researchers to study the density, velocity profiles, and

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

• simulations of irradiation-driven transformations of complex molecular systems by means of the advanced software packages MBN Explorer and MBN Studio. Atomistic simulations performed following the formulated protocol provide valuable insights into the fundamental mechanisms of electron-induced precursor

• molecule, on a SiO2 surface. The simulations reveal the processes driving the initial phase of nanostructure formation during FEBID, including the nucleation of Pt atoms and the formation of small metal clusters on the surface, followed by their aggregation and the formation of dendritic platinum

• fundamental mechanisms of electron-induced precursor fragmentation and the corresponding mechanisms of nanostructure formation and growth using FEBID. Until recently, most computer simulations of FEBID and nanostructure growth have been performed using a Monte Carlo approach and diffusion–reaction theory [2

Criteria ruling particle agglomeration

• Dieter Vollath

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

• direction of a minimum of the free enthalpy. In this context, one may observe mechanisms leading to a reduction of the surface energy or controlled by the van der Waals interaction. Additionally, the ensemble may arrange in the direction of a maximum of the entropy. Simulations based on Monte Carlo methods

• teach that, in case of any energetic interaction of the particles, the influence of the entropy is minor or even negligible. Complementary to the simulations, the extremum of the entropy was determined using the Lagrange method. Both approaches yielded identical result for the particle size distribution

• increase at low numbers of collisions to a maximum at Ntot/2, followed by a steep decrease. These relations are depicted in Figure 4 for an ensemble of Ntot = 108 particles. The graphs show a maximum in the vicinity of Ntot/2. Because of the unavoidable fluctuations, simulations cannot determine the exact

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

• frequency – recall that z = eαeiω), for circles with different radii on the z-plane. The radii of the circles are respectively 1.01, 1.2, 2, and 2.5. As the figures show, the retardance calculated from the simulations and the theoretical values match closely with an error below 0.25%. Notice that the

• compliance, storage compliance and absolute retardance. Material parameters used in the simulations. Supporting Information The Supporting Information features derivations of generalized Voigt and Maxwell–Wiechert models in the Laplace and the z-domains; a brief overview of Fourier, modified Fourier

• , Laplace, and Z-transforms; additional data illustrating the misrepresentation of the system in the Fourier domain and additional data from AFM simulations; and, finally, a detailed analysis of loss and storage as a function of frequency and their estimation from modified Fourier transforms. Supporting

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

• interaction volume, a steady-state condition of ion impurity concentration and number of induced defects is reached. The EBSD measurements and Monte Carlo simulations indicate that when this steady-state condition is reached more quickly, which can be achieved using high-energy Ne ions at a glancing incidence

• transmission electron microscopy (STEM), TEM, TEM selected area electron diffraction (SAED), and TEM dark-field (DF) measurements. The results for each experiment are compared to those of a non-irradiated area of the Cu TEM grid. Monte Carlo simulations of the occurring ion–solid interactions are evaluated to

• produce artefacts that would compromise the TEM analysis. Monte Carlo simulations were performed using the program Stopping and Range of Ions in Matter (SRIM) to better understand the underpinning ion–solid interactions for the different settings [22]. The extent of created dislocations, vacancies as well

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• design often relies on non-planar adsorbates with bulky spacer groups, which can adopt various conformations. From a theoretical point of view, finding the energetically most stable conformational structure can be challenging and costly because conventional atomistic simulations are often limited to the

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

• is caused by subtractive (in the AP state) and additive (in the P state) influences of ferromagnetic exchange fields from neighbor F-layers, which are detrimental to the spin-singlet order in S′ [1][2][3][4][5][6][7][8]. Simulations in Figure 1c demonstrate the tunability of superconductivity in such

• seen by the small (milliohms) resistance values. Here we observe the simplest MR curves, most consistent with the two-state theoretical prediction based on mono-domain simulations, as in Figure 1c. Namely, a P state at high field with large Rxx (suppressed superconductivity) and an AP state at low

• that the initial stage of remagnetization from P to AP state is fully reversible, see curve-1 in Figure 3b. Micromagnetic simulations show that such a stage corresponds to monodomain coherent rotation of magnetizations in neighbor F-layers in opposite directions in a scissor-like manner [34][37]. As

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

• , such as low signal-to-noise (S/N) ratio or high emitter (photon) density, leading to blurry images. The network can be trained either on experimental or on simulated images. Simulations are based on the well-understood physics of the image degradation process to generate training images. The simulated

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

• ) composites under shear loading are investigated by molecular dynamics simulations. The effects of different temperatures, graphene chirality, repeat layer spacing, and grain size on the mechanical properties, such as failure mechanism, dislocation, and shear modulus, are observed. The results indicate that

• ) simulations of shear loading with different metal layer spacings and grain sizes are conducted. Besides, the temperature effect is also considered since metal lattices become disordered and soften with an increase in temperature [29][30]. Gayk et al. revealed the relationship between different potentials and

• 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

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

• ][53]. The abovementioned reconstruction algorithms are mostly aimed at real-scanned images, but they could have better applications in molecular simulation to speed up simulations. In this paper, BCS and SRCNN methods are used to reconstruct the molecular simulation images to reduce simulation time

• dynamics simulation To test the effectiveness of the reconstruction algorithms we perform molecular dynamics simulations of AFM imaging in different conditions. The dynamic process (AM mode) and quasi-static process (the relative position of tip–sample remains unchanged in the simulation) are separately

• carried out. The simulation protocol for computing tip–sample interactions is similar to our previous work [54]. In the simulations, the tip consists of silicon atoms and it changes among different shapes, including cone, hemisphere, and single silicon atom. The conical tip height is 13 Å, the opening

Physical constraints lead to parallel evolution of micro- and nanostructures of animal adhesive pads: a review

• Thies H. Büscher and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2021, 12, 725–743, doi:10.3762/bjnano.12.57

• functional AMS on the euplantulae of phasmids. The transitions observed in the simulations were used to evaluate the adaptability of the structures, transitions between the structural patterns which could reflect the evolutionary processes, to re-evaluate the potential ancestral state of stick insect AMS

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

• insights, there is a knowledge gap in the understanding of metal thin film nucleation on 2D materials [28]. We showed that we can investigate the first stages of thin film nucleation on 2D materials with first principles simulations, using the example of small Cun structures on an MoS2 monolayer (ML). MoS2

• first insight into how the presence of such a vacancy might change the interaction between the metal and the ML, we repeat the simulations of the adsorption of single metal atoms and M4 structures on a defective MoS2 ML with a single S vacancy. This was carried out before in our previous work with Cu

Electromigration-induced formation of percolating adsorbate islands during condensation from the gaseous phase: a computational study

• Alina V. Dvornichenko,
• Vasyl O. Kharchenko and
• Dmitrii O. Kharchenko

Beilstein J. Nanotechnol. 2021, 12, 694–703, doi:10.3762/bjnano.12.55

• islands during condensation from the gaseous phase. We will show that the elongated morphology of adsorbate islands remains stable if the electric field is turned off. Keywords: adsorptive systems; electromigration; numerical simulations; pattern formation; thin films; Introduction The processes of

• of adsorbate concentration on the substrate. After that, we discuss the results of numerical simulations. The main conclusions are collected in the last section. Model In order to describe the evolution of the adsorbate concentration on the first growing layer of the multilayer system during

• strength ε extends the domain of α and k∥ in which patterning is possible. Numerical simulations In order to perform numerical simulations of the process of pattern formation during deposition we will proceed in a manner closely related to [63][64]. We will solve numerically Equation 4 on a two-dimensional

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

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• ]. Recently, however, Zhang et al. used STM in combination with DFT simulations to study the variation of the local work function and bandgap within the Moiré superlattice and found that the variation depends on the angle of the Moiré with respect to the substrate lattice, but inferred only marginal structure

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

• can also be used as sensors [22]. TENGs, originally proposed by Prof. Zhongling Wang [23], are microgenerators that convert mechanical energy into electrical energy based on the triboelectric effect [24]. In most TENG simulations, a triboelectric polymer material is in direct contact with an electrode

• triboelectric materials is helpful for distinguishing different gases. It is noted that water or humidity can degrade the surface charge density of the electrification surfaces in an actual experiment. We will carry out further investigations in the future. Conclusion Simulations of three differently shaped

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

• -donor or electron-acceptor centres is involved in the interaction with the Ag surface [51]. To bring the Monte-Carlo simulations closer to a real system, short-range interactions between the nearest neighbours were also assumed besides the movement rules defined by the DLL algorithm itself (providing an

• been previously observed for polymer chains [49][50], even when only excluded volume interactions were assumed. Previous works [38][39], as well as the performed simulations, support the finding presented herein in which silver nanoparticles are able to induce surface-enhanced Raman scattering of water

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

• contamination and averaging effects in KPFM [51]. Conclusion In conclusion, a novel corrugated reconstruction of KBr was observed on Ir(111) by nc-AFM and confirmed by DFT simulations. It is attributed to the lattice symmetry of KBr with respect to the iridium substrate in one direction and a self-adjustment in

• the orthogonal direction forming characteristic stripe patterns. The DFT simulations verify these alternating structures and predict repeating KBr clusters that form a double-row structure connected by Br− ions, which are more strongly bound to the Ir substrate, while the K+ ions keep stable. The work

Colloidal particle aggregation: mechanism of assembly studied via constructal theory modeling

• Scott C. Bukosky,
• Sukrith Dev,
• Monica S. Allen and
• Jeffery W. Allen

Beilstein J. Nanotechnol. 2021, 12, 413–423, doi:10.3762/bjnano.12.33

• increase in the coordination number. We should note that the results presented here assume the self-assembly of monodisperse spherical particles suspended in a monovalent salt solution arranged in a uniform starting configuration. Given the Brownian nature of colloidal particles, future simulations should

• account for the randomness of colloidal suspensions. These simulations should also include the effects from polydisperse particle mixtures or divalent salt solutions, and they should be able to handle the addition of an external stimulus that could facilitate and drive particle assembly. Conclusion We

Intracranial recording in patients with aphasia using nanomaterial-based flexible electronics: promises and challenges

• Qingchun Wang and
• Wai Ting Siok

Beilstein J. Nanotechnol. 2021, 12, 330–342, doi:10.3762/bjnano.12.27

• required. As a continuously evolving field, nanotechnology presents a promising strategy to overcome the current technical limitations of the iEEG method. Flexible electronics have been generated that can be invasively implanted in the brain to collect recordings and simulations of neural activities with

Exploring the fabrication and transfer mechanism of metallic nanostructures on carbon nanomembranes via focused electron beam induced processing

• Christian Preischl,
• Linh Hoang Le,
• Elif Bilgilisoy,
• Armin Gölzhäuser and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2021, 12, 319–329, doi:10.3762/bjnano.12.26

• was dosed through a nozzle with an inner diameter of 3 mm and a distance of approximately 12 mm to the sample surface. Based on simulations using GIS Simulator (version 1.5) [36], the local pressure increase on the sample surface was calculated to approximately 30×. For a fixed background pressure of

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

• detector is able to determine the thickness of membranes with sub-nanometer precision by quantitatively evaluating the image signal and comparing the results with Monte Carlo simulations. The thickness determined by the dark-field transmission detector is compared to X-ray photoelectron spectroscopy and

• energy-filtered transmission electron microscopy measurements. Keywords: carbon nanomembranes; dark field; helium ion microscopy (HIM); scanning transmission ion microscopy (STIM); SRIM simulations; Introduction Throughout the past decade, the helium ion microscope (HIM) has emerged as a versatile

• between holder in the specimen chamber and objective lens. The required hole sizes depend on the deflection angles, which are determined by beam energy, sample thickness, and sample material. The angles can be predicted using Monte Carlo simulations, which yield information about the relevant range of