arXiv subjects

Andrey Sarikov

Publications and source records attributed to Andrey Sarikov.

6 recordsLinked to original sources

arXiv2026

Molecular dynamics simulation study of mechanical properties of 3C-SiC with extended defects

In this study, large-scale molecular dynamics simulations with the Vashishta potential and the analytic bond-order potential (ABOP) were performed to investigate the effect of extended defects on the elastic properties of cubic silicon carbide (3C-SiC). Specifically, we focused on systems containing Shockley partial dislocations terminating stacking faults, along with double and triple dislocation complexes. The changes in the independent elastic stiffness constants C11, C12 and C44 upon varying the mentioned extended defects concentrations were quantified. Using the values of these constants, the effective bulk, shear, and Young's moduli were calculated for different defect types and concentrations. The moduli were calculated along particular crystallographic directions aligned with the mentioned defect configurations as well as evaluated using Voigt-Reuss-Hill averaging to provide overall orientation-independent characterization of the defect-altered lattice. The obtained results reveal a general trend of diminishing the material's stiffness with increasing densities of Shockley partial dislocations and dislocation complexes. Depending on the defect configuration, the average elastic moduli decrease by up to approximately 6 % with the Vashishta potential and up to about 4 % using the analytic bond-order potential. At this, triple dislocation complexes induce smaller perturbations. These findings demonstrate that extended defect networks can measurably modify the elastic response of 3C-SiC and should be considered in further scientific research and practical applications of this material.

cond-mat.mtrl-sci↗

arXiv2025

3D lattice Monte Carlo modeling of morphology formation of Si/SiOx nanocomposites during phase separation of nonstoichiometric Si oxide films

In this paper, a three-dimensional lattice model based on the Monte Carlo approach is presented. This model is developed to investigate the kinetics of morphology change during phase separation in nonstoichiometric Si oxide (SiOx, x < 2) films. The model takes into account the SiOx local atomic structure and probabilistic migration of oxygen atoms driven by the tendency of free energy minimization. The influence of the initial SiOx stoichiometry index x and film thickness on the morphology of the precipitated Si phase in the Si oxide matrix is analyzed. The morphology of the Si phase is shown to critically depend on the initial SiOx stoichiometry. Namely, isolated Si nanoparticles form at low excess Si content (x >= 1.4), while interconnected Si networks always appear at x <= 0.8. A dimensional effect on the morphology of the Si phase is revealed. Namely, reducing the film thickness imposes geometric constraints on the Si network formation. The percolation threshold is found to shift from xp ~= 1.35 for the bulk-like SiOx layers to xp ~= 0.85 for the quasi-two-dimensional films. The transition to the bulk material behavior is observed at a SiOx thickness of approximately 4.2 nm.

cond-mat.mtrl-sci↗

arXiv2025

Dispersed multi-walled carbon nanotubes in polyvinyl butyral matrix for transparent ionic conductive films

In this work, we develop methods for increasing the dispersion degree of agglomerated multiwalled carbon nanotubes with subsequent introduction of them into polyvinyl butyral to create transparent conductive films. The influence of proton and a-proton solvents in combination with potassium triiodide (KI3) as a redox component for oxidation of the multiwalled carbon nanotubes surface, which reduces agglomeration due to electrostatic repulsion, is investigated. It is demonstrated that a-proton solvent cyclohexanone ensures a smaller size of the agglomerates (30-300 nm, with a maximum of ~145 nm) compared to proton solvent propyl alcohol (100-3000 nm, with a maximum of ~920 nm). The reduced aggregation is associated with the formation of oxygen-containing functional groups (C=O, C-O, C-O-C, and COO), which increase electrostatic stabilization. The impedance analysis showed that the constant component of the conductivity in the samples with multiwalled carbon nanotubes and a-proton solvent shifts to frequencies of ~104 rad/s after the addition of the redox component, which indicates the formation of ion-conducting channels and stabilization of the jump charge transfer.

cond-mat.mtrl-sci↗

arXiv2025

Stable partial dislocation complexes in GaN as charge carrier lifetime modifiers for terahertz device applications by molecular dynamics and first-principle simulations

Wurtzite GaN is a promising material for applications in photoconductive THz radiation sources. For this purpose, the photogenerated charge carriers lifetime of the order of tenths of picoseconds is required. A controllable lifetime reduction may be considered to achieve by creating recombination active stable dislocation complexes formed by mobile basal-plane Shockley partial dislocations (PDs). In this work, formation pathways and stability of PD complexes in basal planes of wurzite GaN are studied by molecular dynamics (MD) simulations. The simulations reveal the formation of stable complexes by attractive interaction of two 30° or two 90° PDs with opposite Burgers vectors located in consecutive (0001) planes. Ones formed, these complexes change neither their positions, not the atomic configurations during simulated anneal at 1500 K up to the times of 5 ns. The MD results are used as an input for density functional theory calculations to refine the atomic structures of the complex cores and to investigate their electronic properties. The calculated band structures of GaN with 30°-30° and 90°-90° dislocation complexes indicate localized energy levels in the band gap near the top of the valence band and the conduction band bottom. The calculations of the partial electronic states density confirm the possibility of electron-hole recombination between the states localized at the PD complex cores. These recombination characteristics are distinctly reflected in the calculated absorption spectra. We conclude that creating such PD complexes in required concentration may be a tool for tailoring the recombination properties of wurtzite GaN for THz radiation generation applications.

cond-mat.mtrl-sci↗

arXiv2021

In-plane selective area InSb-Al nanowire quantum networks

Strong spin-orbit semiconductor nanowires coupled to a superconductor are predicted to host Majorana zero modes. Exchange (braiding) operations of Majorana modes form the logical gates of a topological quantum computer and require a network of nanowires. Here, we develop an in-plane selective-area growth technique for InSb-Al semiconductor-superconductor nanowire networks with excellent quantum transport properties. Defect-free transport channels in InSb nanowire networks are realized on insulating, but heavily mismatched InP substrates by 1) full relaxation of the lattice mismatch at the nanowire/substrate interface on a (111)B substrate orientation, 2) nucleation of a complete network from a single nucleation site, which is accomplished by optimizing the surface diffusion length of the adatoms. Essential quantum transport phenomena for topological quantum computing are demonstrated in these structures including phase-coherent transport up to 10 $μ$m and a hard superconducting gap accompanied by 2$e$-periodic Coulomb oscillations with an Al-based Cooper pair island integrated in the nanowire network.

cond-mat.mes-hall↗

arXiv2020

Origin and nature of killer defects in 3C-SiC for power electronic applications by a multiscale atomistic approach

3C-SiC epitaxially grown on Si displays a large wealth of extended defects. In particular, single, double and triple stacking faults (SFs) are observed in several experiments to coexist. Overabundance of defects has so far limited the exploitation of 3C-SiC/Si for power electronics, in spite of its several ideal properties (mainly in terms of wide gap, high breakdown fields and thermal properties) and the possibility of a direct integration in the Si technology. Here we use a multiscale approach, based on both classical molecular dynamics (MD) simulations and first-principle calculations, to investigate in-depth the origin, nature and properties of most common 3C-SiC/Si(001) extended defects. Our MD simulations reveal a natural path for the formation of partial dislocation complexes terminating both double and triple SF's. MD results are used as input for superior DFT calculations, allowing us to better determine the core structure and to investigate electronic properties. It turns out that the partial dislocation complexes terminating double and triple SFs are responsible for the introduction of electronic states significantly filling the gap. On the other hand, individual partial dislocations terminating single SFs only induce states very close to the gap edge. We conclude that partial dislocation complexes, in particular the most abundant triple ones, are killer defects in terms of favoring leakage currents. Suggestions coming from theory/simulations for devising a strategy to lower their occurrence are discussed.

cond-mat.mtrl-sci↗