All posts under tag "Condensed Matter"
The missing piece in the jigsaw of silicon photonics is a light source that can be easily incorporated into the standard silicon fabrication process. Recent advances in the development of atomically thin layers of semiconducting transition metal dichalogenides (TMDs), with direct bandgaps in the nea
A quite general device analysis method that allows the direct evaluation of optical and recombination losses in crystalline silicon (c-Si)-based solar cells has been developed. By applying this technique, the optical and physical limiting factors of the state-of-the-art solar cells with ~20% efficie
Genetic robustness, the preservation of an optimal phenotype in the face of mutations, is critical to the understanding of evolution as phenotypically expressed genetic variation is the fuel of natural selection. The origin of genetic robustness, whether it evolves directly by natural selection or i
We report on the interfacial electronic properties of HfO2 gate dielectrics both, with GaN towards normally-OFF recessed HEMT architectures and the AlGaN barrier for normally-ON AlGaN/GaN MISHEMTs for GaN device platforms on Si. A conduction band offset of 1.9 eV is extracted for HfO2/GaN along with
Monolayer two-dimensional transitional metal dichalcogenides, such as MoS2, WS2 and WSe2, are direct band gap semiconductors with large exciton binding energy. They attract growing attentions for opto-electronic applications including solar cells, photo-detectors, light-emitting diodes and photo-tra
Voltage control effects provide an energy-efficient means of tailoring material properties, especially in highly integrated nanoscale devices. However, only insulating and semiconducting systems can be controlled so far. In metallic systems, there is no electric field due to electron screening effec
Boltzmann's struggle with a derivation of the Second Law of Thermodynamics is sketched. So is his first derivation of the connection between entropy and probability in 1877. Planck's derivation and quantum mechanical modifications of Boltzmann's connection between entropy probability are given next.
The possibility of hybridizing collective electronic motion with mid-infrared (mid-IR) light to form surface polaritons has made van der Waals layered materials a versatile platform for extreme light confinement and tailored nanophotonics. Graphene and its heterostructures have attracted particular
We report a gas eruption phenomenon caused by electrolysis of liquid Ga-In alloy in an electrolyte, especially NaOH solution. A volcanic eruption-like blowout of gas occurred from the orifice on the alloy surface. In addition to gas plume, large gas bubbles were also generated and the total gas yiel
The exceptional conducting nature of graphene makes it a viable candidate for enhancing the effectiveness of photocatalytic and biomedical nanomaterials. Herein, the immobilization of monodispersed silicon dioxide (SiO2) nanoparticles on multiple graphene layers is demonstrated for intercalation of
Experiments, numerical simulations and an analytic model were developed to elucidate the effects of noise in the synchronized state of a tunnel junction based spin torque nano oscillator (STNO). It is demonstrated that in the in plane magnetized structure, while the frequency is locked, much higher
Numerical models indicate that collective animal behaviour may emerge from simple local rules of interaction among the individuals. However, very little is known about the nature of such interaction, so that models and theories mostly rely on aprioristic assumptions. By reconstructing the three-dime
Equilibrium systems evolve according to Detailed Balance (DB). This principe guided development of the Monte-Carlo sampling techniques, of which Metropolis-Hastings (MH) algorithm is the famous representative. It is also known that DB is sufficient but not necessary. We construct irreversible deform
Some Bravais lattices have a particular geometry that can slow down the motion of Bloch electrons by pre-localization due to the band-structure properties. Another known source of electronic localization in solids is the Coulomb repulsion in partially filled d- or f-orbitals, which leads to the form
The exploitation of the excellent intrinsic electronic properties of graphene for device applications is hampered by a large contact resistance between the metal and graphene. The formation of edge contacts rather than top contacts is one of the most promising solutions for realizing low ohmic conta
Materials design and development typically takes several decades from the initial discovery to commercialization with the traditional trial and error development approach. With the accumulation of data from both experimental and computational results, data based machine learning becomes an emerging
An approximate many-body theory incorporating two-body correlations has been employed to calculate low-lying collective multipole frequencies in a Bose-Einstein condensate containing $A$ bosons, for different values of the interaction parameter $lambda=frac{Aa_{s}}{a_{ho}}$. Significant difference f
We study the magnetocapacitance (MC) effect and magnetoelectric (ME) coupling in spin-flop driven antiferromagnet Co4Ta2O9. The magnetocapacitance data at high magnetic fields are analyzed by phenomenological Ginzburg-landau theory of ferroelectromagnets and it is found that change in dielectric con
It is known that many potent, often aromatic drugs are water insoluble, which has hampered their use for disease treatment. In this work, we functionalized nano-graphene oxide (NGO), a novel graphitic material, with branched polyethylene glycol (PEG) to obtain a biocompatible NGO-PEG conjugate stabl
We propose a route towards creating a metamaterial that behaves as a photonic Chern insulator, through homogenization of an array of gyromagnetic cylinders. We show that such an array can exhibit non-trivial topological effects, including topologically non-trivial band gaps and one-way edge states,
Spin accumulation induced by spin-orbit coupling is experimentally quantified in stack with in-plane magnetic anisotropy via the contribution of spin accumulation to Hall resistances. Using a biasing direct current the spin accumulation within the structure can be tuned, enabling quantification. Qua
A continuous-time quantum walk is investigated on complex networks with the characteristic property of community structure, which is shared by most real-world networks. Motivated by the prospect of viable quantum networks, I focus on the effects of network instabilities in the form of broken links,
A single protein molecule is regarded as a contact network of amino-acid residues. Some studies have indicated that this network is a small world network (SWN), while other results have implied that this is a fractal network (FN). However, SWN and FN are essentially different in the dependence of th
In this article, we report the process induced variation in the characteristics of PECVD deposited and thermally grown silicon dioxide (SiO2) thin film. We find key differences in the porosity, arrangement of the nano-pores, surface roughness, refractive index and electrical resistivity of the SiO2
With ultra-fast writing capacity and high reliability, the spin-orbit torque is regarded as a promising alternative to fabricate next-generation magnetic random access memory. However, the three-terminal setup can be challenging when scaling down the cell size. In particular, the thermal stability i
The orthorhombic phase of Si-doped Fe carbide is synthesized at high pressures and temperatures using laser-heated diamond anvil cell (LHDAC), followed by its characterization using X-ray diffraction (XRD) measurements, Transmission Electron Microscopy (TEM), and Raman spectroscopy. High-pressure XR
Annealing treatment is an important step of rolling deformation that contributes to microstructural evolution and leads to the significant changes in damping capacity. Damping capacities were analyzed in the parallel to rolling direction at 1 and 10 Hz respectively. It was found that severe plastic
We estimate by Monte Carlo simulations the configurational entropy of $N$-steps polygons in the cubic lattice with fixed knot type. By collecting a rich statistics of configurations with very large values of $N$ we are able to analyse the asymptotic behaviour of the partition function of the problem
We measured Young's modulus at temperatures ranging from 20 to 100 ^{circ}$C for a collagen fibril taken from rat's tendon. The hydration change under heating and the damping decrement were measured as well. At physiological temperatures $25-45^{circ}$C Young's modulus decreases, which can be interp
Biological systems reach organizational complexity that far exceeds the complexity of any known inanimate objects. Biological entities undoubtedly obey the laws of quantum physics and statistical mechanics. However, is modern physics sufficient to adequately describe, model and explain the evolution
As the focus of applied research in topological insulators (TI) evolves, the need to synthesize large-area TI films for practical device applications takes center stage. However, constructing scalable and adaptable processes for high-quality TI compounds remains a challenge. To this end, a versatile
Room-temperature (RT) Pulsed Cathodoluminescence (PCL) spectra of a set of pure synthetic (both crystalline and amorphous) silicon dioxide materials were studied. It is shown, that the PCL spectra of all samples (both amorphous and crystalline) possess a separate band at 495 nm (2.5 eV). This band i
We present an improved parallel algorithm for the enumeration of fixed benzenoids B_h containing h hexagonal cells. We can thus extend the enumeration of B_h from the previous best h=35 up to h=50. Analysis of the associated generating function confirms to a very high degree of certainty that $B_h s
The adsorption behavior of toxic gas molecules (NO, CO, NO2, and NH3) on graphene-like BC3 are investigated using first-principle density functional theory (DFT). The most stable adsorption configurations, adsorption energies,binding distances,charge transfers,electronic band structures,and the cond
Futures trading is the core of futures business, and it is considered as one of the typical complex systems. To investigate the complexity of futures trading, we employ the analytical method of complex networks. First, we use real trading records from the Shanghai Futures Exchange to construct futur
We examine the effective counterion-mediated electrostatic interaction between two like-charged dielectric cylinders immersed in a continuous dielectric medium containing neutralizing mobile counterions. We focus on the effects of image charges induced as a result of the dielectric mismatch between
We propose a method for efficiently coupling the finite element method with atomistic simulations, while using molecular dynamics or kinetic Monte Carlo techniques. Our method can dynamically build an optimized unstructured mesh that follows the geometry defined by atomistic data. On this mesh, diff
Molecular-dynamics algorithms for systems of particles interacting through discrete or 'hard' potentials are fundamentally different to the methods for continuous or 'soft' potential systems. Although many software packages have been developed for continuous potential systems, software for discrete
To ensure the practical application of atomically thin transition metal dichalcogenides, it is essential to characterize their structural stability under external stimuli such as electric fields and currents. Using vacancy monolayer islands on TiSe2 surfaces as a model system, for the first time we
Using a recently developed mesoscopic theory of protein dielectrics, we have calculated the salt bridge energies, total residue electrostatic potential energies, and transfer energies into a low dielectric amyloid-like phase for 12 species and mutants of the prion protein. Salt bridges and self ener
The focus of this article is on entropy and Markov processes. We study the properties of functionals which are invariant with respect to monotonic transformations and analyze two invariant 'additivity' properties: (i) existence of a monotonic transformation which makes the functional additive with r
Investigating the interaction of electron beams with materials and light has been a field of research since more than a century. The field was advanced theoretically by the raise of quantum mechanics and technically by the introduction of electron microscopes and accelerators. It is possible nowaday
The kinetics of the transformation from the hexagonal packed cylinder (HEX) phase to the face-centered-cubic (FCC) phase was simulated using Brownian Dynamics for an ABA triblock copolymer in a selective solvent for the A block. The kinetics was obtained by instantaneously changing either the temper
We propose a biologically motivated quantity, twinness, to evaluate local similarity between nodes in a network. The twinness of a pair of nodes is the number of connected, labeled subgraphs of size n in which the two nodes possess identical neighbours. The graph animal algorithm is used to estimate
We investigate the problem of growing clusters, which is modeled by two dimensional disks and three dimensional droplets. In this model we place a number of seeds on random locations on a lattice with an initial occupation probability, $p$. The seeds simultaneously grow with a constant velocity to f
We study synchronization in the context of network traffic on a $2-d$ communication network with local clustering and geographic separations. The network consists of nodes and randomly distributed hubs where the top five hubs ranked according to their coefficient of betweenness centrality (CBC) are
We study pseudogap behaviors of ultracold Fermi gases in the BCS-BEC crossover region. We calculate the density of states (DOS), as well as the single-particle spectral weight, above the superfluid transition temperature $T_{rm c}$ including pairing fluctuations within a $T$-matrix approximation. We
In the context of statistical physics, Chandrasekharan and Wiese recently introduced the emph{fermionant} $Ferm_k$, a determinant-like quantity where each permutation $pi$ is weighted by $-k$ raised to the number of cycles in $pi$. We show that computing $Ferm_k$ is #P-hard under Turing reductions f
It is shown that a slip wave solution exists for anti-plane sliding of an elastic layer on an elastic half-space. It is a companion solution to the well-known Love wave solution.
Recent studies have shown the possibility of water transport across carbon nanotubes, even in the case of nanotubes with small diameter (0.822 nm). In this case, water shows subcontinuum transport following an ordered 1D structure stabilized by hydrogen bonds. In this work, we report MD simulations
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