Binary Lattice Research Articles

Condensate formation in a chiral lattice gas

Abstract We investigate the formation of condensates in a binary lattice gas in the presence of chiral interactions. These interactions differ between a given microscopic configuration and its mirror image. We consider a two dimensional lattice gas with nearest-neighbour interactions to which we add interactions involving favoured local structures that are chiral. We focus on favoured local structures that have the shape of the letter L and explore condensate formation through simulations and analytical calculations. At low temperature, this model can exhibit four different phases that are characterised by different periodic tiling patterns, depending on the strength of interactions and the chemical potential. When particle numbers are conserved, some of these phases can coexist. We analyse the structure and surface tension of interfaces between coexisting phases and determine the shapes of minimal free energy of crystalline condensates. We show that these shapes can be quadrilaterals or octagons of different orientation and symmetry.

Realization of Two-Dimensional Intrinsic Polar Metal in a Buckled Honeycomb Binary Lattice.

Structural topology and symmetry of a two-dimensional (2D) network play pivotal roles in defining its electrical properties and functionalities. Here, a binary buckled honeycomb lattice with C3v symmetry, which naturally hosts topological Dirac fermions and out-of-plane polarity, is proposed. It is successfully achieved in a group IV-V compound, namely monolayer SiP epitaxially grown on Ag(111) surface. Combining first-principles calculations with angle-resolved photoemission spectroscopy, the degeneration of the Dirac nodal lines to points due to the broken horizonal mirror symmetry is elucidated. More interesting, the SiP monolayer manifests metallic nature, which is mutually exclusive with polarity in conventional materials. It is further found that the out-of-plane polarity is strongly suppressed by the metallic substrate. This study not only represents a breakthrough of realizing intrinsic polarity in 2D metallic material via ingenious design but also provides a comprehensive understanding of the intricate interplay of many exotic low-dimensional quantum phenomena.

Revealing the Role of Binary Distortion in PMS Activation over Spinel toward Efficient New Pollutants Removal

AbstractImproving peroxymonosulfate (PMS) activation efficiency to enhance simultaneous generation of radicals and non‐radicals is essential for removing new pollutants (NPs) in complex waters. However, achieving this with standard lattice‐structured heterogeneous catalysts remains challenging due to inefficient electron transfer. Here, CuCo2O4 properties are successfully tuned by controlling lattice distortion, enabling simultaneous PMS oxidation and reduction. Unlike the slow rate of electron transfer in heterogeneous metal catalysts with standard lattice structures, the highly active binary lattice distortion in CuCo2O4 alters the structure and electron distribution, exposes more Cu and Co sites, lowers the PMS adsorption barriers, and realizes the synergistic production of SO4•−/•OH), and 1O2. The k‐value for ciprofloxacin is as high as 17.83 min−1 M−1, 29.42 times higher than that with non‐binary lattice distortion. Additionally, the developed intermittent reactor consistently maintains a removal rate above 95% over five cycles in actual wastewater treatment scenarios. This work provides a new avenue for achieving the removal of new pollutants in complex water bodies.

Controlling the Motion of Interfaces in Capillary Channels with Non-uniform Surface Wettability

The use of self-driven flows in microfluidic devices attracts many researchers as the external flow-driving mechanism is diminished or eliminated. One of the mechanisms providing such motions is generating a pressure difference across interfaces as in the case of the motion in capillary tubes. The capillarity, namely, the pressure difference across the interface due to its curvature drives the motion. This pressure depends on the interaction with the capillary walls and is controlled if one varies the surface energy of the walls. In this study, we search for the effects of surface energy on the motion of interfaces in capillary-driven flow. To this end, we model the motion of fluid particles in a capillary channel and integrate the governing equations using the binary lattice Boltzmann method for the two-phase flow. We, first, validate our solver for canonical static and dynamic problems. We, then, discuss two main contributions; we show how to deviate the interface speed from the ones moving in channels with uniform wall energies and discuss the conditions under which such an interface stagnates (like a passive valve in a channel). Tuning the wettability of the channel walls, we provide a simple condition for stopping the interface: the summation of the equilibrium contact angles interface make with the channel walls at the bottom and top wall need to satisfy $\theta_{eq}^{top}+\theta_{eq}^{bot} \geq \pi$. Configurations and wetting properties of different wettability regions play major roles together

2D Jackiw–Rebbi and trivial localized states in square interfaced binary waveguide lattices

We investigate optical analogs of two-dimensional (2D) Jackiw–Rebbi (JR) states and 2D trivial localized states in square interfaced binary waveguide lattices in the linear and nonlinear regimes of Kerr type. The 2D JR states can be formed in the square interfaced binary lattice during propagation of optical beams and turn out to be quite robust, especially in the linear and defocusing nonlinearity regime where established 2D JR state profiles are well conserved during propagation. The established profiles of nonlinear 2D JR states formed during propagation agree well with exact solutions obtained by using the Newton–Raphson method. The 2D nonlinear trivial localized states found by the successive approximation method are much broader than 2D JR states with the same peak amplitudes. The 2D JR states can also be well trapped within the central interface of the lattices even in the presence of an initial tilt of the input beam which can easily displace 2D trivial localized states in square interfaced binary waveguide lattices, 2D Dirac solitons in perfectly periodic binary waveguide lattices and other solitonic structures in the continuous media.

DMD-based compact SIM system with hexagonal-lattice-structured illumination.

In this study, we developed a novel, compact, and efficient structured illumination microscopy (SIM) system, to our best knowledge. A binary hexagonal lattice pattern was designed and implemented on a digital micromirror device (DMD), resulting in a projection-based structured-light generation. By leveraging the combination of the high-speed switching capability of the DMD with a high-speed CMOS camera, the system can capture 1024×1024 pixels images at a 200fps frame rate when provided with sufficient illumination power. The loading of the hexagonal lattice pattern reduces the number of images required for reconstruction to seven, and by utilizing the DMD modulating characteristics on the illumination path, there is no need to use bulky mechanical structures for phase shifting. We designed a compact system with 110m m×150m m×170m m dimensions that displayed a 1.61 resolution enhancement for fluorescent particle and biological sample imaging.

Interfacial Properties of Fluids Exhibiting Liquid Polyamorphism and Water-Like Anomalies.

It has been hypothesized that liquid polyamorphism, the existence of multiple amorphous states in a single-component substance, may be caused by molecular or supramolecular interconversion. A simple microscopic model [Caupin and Anisimov, Phys. Rev. Lett. 2021, 127, 185701] introduces interconversion in a compressible binary lattice to generate various thermodynamic scenarios for fluids that exhibit liquid polyamorphism and/or water-like anomalies. Using this model, we demonstrate the dramatic effects of interconversion on the interfacial properties. In particular, we find that the liquid-vapor surface tension exhibits either an inflection point or two extrema in its temperature dependence. Correspondingly, we observe anomalous behavior of the interfacial thickness and a significant shift in the location of the concentration profile with respect to the location of the density profile.

Fractionality and PT symmetry in a square lattice

We study the spectral stability of a 2D discrete Schr\"{o}dinger equation on a square lattice, in the simultaneous presence of a fractional Laplacian and $\cal{PT}$ symmetry. For that purpose, we compute the plane-wave spectrum in closed form, as a function of the gain/loss parameter and the fractional exponent. Examination of the spectrum reveals that an increase of the gain/loss parameter favors the early appearance of complex eigenvalues, thus is, the onset of a broken ${\cal PT}$ symmetry. On the other hand, as the fractional exponent decreases from unity, at a critical value a gap opens up separating the upper and lower bands, and the spectrum becomes real. Further decrease of the exponent increases the width of the gap and the system remains in the $\cal{PT}$-symmetric phase down to a vanishing value of the fractional exponent. Examination of the density of states and the participation ratio reinforce these observations and lead one to conclude that, unlike the standard, non-fractional case where the binary lattice is always in the broken $\cal{PT}$ phase, for the fractional case it is possible to have a symmetric $\cal{P}{\cal T}$ phase in the presence of a finite gain/loss parameter and a small enough fractional exponent.

Minimal Microscopic Model for Liquid Polyamorphism and Waterlike Anomalies.

Liquid polyamorphism is the intriguing possibility for a single component substance to exist in multiple liquid phases. We propose a minimal model for this phenomenon. Starting with a binary lattice model with critical azeotropy and liquid-liquid demixing, we allow interconversion of the two species, turning the system into a single-component fluid with two states differing in energy and entropy. Unveiling the phase diagram of the noninterconverting binary mixture gives unprecedented insight on the phase behaviors accessible to the interconverting fluid, such as a liquid-liquid transition with a critical point, or a singularity-free scenario, exhibiting thermodynamic anomalies without polyamorphism. The model provides a unified theoretical framework to describe supercooled water and a variety of polyamorphic liquids with waterlike anomalies.

Experimental Realization and Phase Engineering of a Two-Dimensional SnSb Binary Honeycomb Lattice

Experimental Realization and Phase Engineering of a Two-Dimensional SnSb Binary Honeycomb Lattice

Anomalous reflection at the interface of binary synthetic photonic lattices

We construct a binary synthetic photonic lattice theoretically by projecting two fiber loops’ light intensity and adjusting the phase distribution precisely. By tuning the phase modulator, wave vector, and propagation constant of an effective waveguide, the interface’s transmittance could be manipulated. Further study on light dynamics shows that the light pulse can achieve total reflection without diffraction and exchanges the light energy in two optical fiber loops completely when phase distribution and wave vector meet certain conditions. Our study may provide a new way to realize optical switches in optical interconnection and optical communication.

Electrostatic properties and stability of Coulomb crystals

AbstractWe calculate the electrostatic properties of more than 20 different Coulomb crystals and study their resistance to small oscillations of the ions around their equilibrium positions (phonon oscillations). We discuss the stability of multicomponent crystals against separation into set of one‐component lattices and for some cases, the influence of energy of the zero‐point vibrations. It is confirmed that the body‐centred cubic (bcc) lattice possesses the lowest electrostatic energy among all one‐component (one type of ion in the elementary cell) crystals. For systems composed of two types of ions (their charge and density numbers are Z1, n1 and Z2, n2, respectively) and for n1 = n2, it is found that the formation of a binary bcc lattice is possible at 1/2.4229 < α < 2.4229, where α ≡ Z2/Z1. Under the same conditions, the NaCl lattice forms at α > 5.197 and α < 0.192. While for n2 = 2n1, the MgB2 lattice is found be stable at 0.1 < α < 0.32. For multicomponent lattices with hexagonal structure (binary hexagonal close‐packed, MgB2 and some others lattices), it is shown that their properties depend on the distance between hexagonal layers and this distance changes with α.

Conformational switching of chiral colloidal rafts regulates raft–raft attractions and repulsions

Membrane-mediated particle interactions depend both on the properties of the particles themselves and the membrane environment in which they are suspended. Experiments have shown that chiral rod-like inclusions dissolved in a colloidal membrane of opposite handedness assemble into colloidal rafts, which are finite-sized reconfigurable droplets consisting of a large but precisely defined number of rods. We systematically tune the chirality of the background membrane and find that, in the achiral limit, colloidal rafts acquire complex structural properties and interactions. In particular, rafts can switch between 2 chiral states of opposite handedness, which alters the nature of the membrane-mediated raft-raft interactions. Rafts with the same chirality have long-ranged repulsions, while those with opposite chirality acquire attractions with a well-defined minimum. Both attractive and repulsive interactions are qualitatively explained by a continuum model that accounts for the coupling between the membrane thickness and the local tilt of the constituent rods. These switchable interactions enable assembly of colloidal rafts into intricate higher-order architectures, including stable tetrameric clusters and "ionic crystallites" of counter-twisting domains organized on a binary square lattice. Furthermore, the properties of individual rafts, such as their sizes, are controlled by their complexation with other rafts. The emergence of these complex behaviors can be rationalized purely in terms of generic couplings between compositional and orientational order of fluids of rod-like elements. Thus, the uncovered principles might have relevance for conventional lipid bilayers, in which the assembly of higher-order structures is also mediated by complex membrane-mediated interactions.

Perfect localization on flat-band binary one-dimensional photonic lattices

The existence of flat bands is generally thought to be physically possible only for dimensions larger than one. However, by exciting a system with different orthogonal states this condition can be reformulated. In this work, we demonstrate that a one-dimensional binary lattice supports always a trivial flat band, which is formed by isolated single-site vertical dipolar states. These flat band modes correspond to the highest localized modes for any discrete system, without the need of any aditional mechanism like, e.g., disorder or nonlinearity. By fulfilling a specific relation between lattice parameters, an extra flat band can be excited as well, with modes composed by fundamental and dipolar states that occupy only three lattice sites. Additionally, by inspecting the lattice edges, we are able to construct analytical Shockley surface modes, which can be compact or present staggered or unstaggered tails. We believe that our proposed model could be a good candidate for observing transport and localization phenomena on a simple one-dimensional linear photonic lattice.

Elastic properties of binary crystals in neutron stars and white dwarfs

Elastic properties play an important role in neutron stars and white dwarfs. They are crucial for modeling stellar oscillations and different processes in magnetars and in degenerate stars which enter compact binary systems. Using electrostatic energy of deformed lattices, we calculate elastic moduli of ordered binary body-centered cubic (sc2) and face-centered cubic (fc2) lattices. We use two methods to determine the effective shear modulus $\mu_{\rm eff}$. We show that $\mu_{\rm eff}$ calculated as a Voigt average agrees with the results obtained from the linear mixing rule. For the sc2 lattice, our calculations are also consistent with the results of numerical simulations of disordered binary body-centered cubic lattice.

Exploring Negative Absolute Temperature Using NetLogo

The possibility of negative temperatures on the Kelvin scale is intriguing and confusing simultaneously. This is because students are used to thinking of temperature as a measure of the internal energy of a system. While this concept is good for many systems, it does not work for all systems. Nuclear and electron spin systems, along with lasers and other energy-bound systems, have negative absolute temperature. These systems have an upper limit to their energy, which arises out of the quantum nature of these systems. This is what gives rise to the negative absolute temperature. Temperature in the broadest sense is related to the change of the entropy of a system for a given change in the internal energy of the system. To help students understand this concept, we have developed a NetLogo model simulation of a binary spin lattice system using the 2D Ising model. For example, imagine a grid of tiny suspended bar magnets, with each magnet only allowed one of two orientations: north pole up or south pole up. NetLogo is a software tool that allows users to program agents that can interact with each other and the environment. Through using this simulation, students in a calculus-based physics or thermodynamics class will get a visual and hands-on experience of the full range of temperatures possible.

Binary Two-Dimensional Honeycomb Lattice with Strong Spin-Orbit Coupling and Electron-Hole Asymmetry.

Two-dimensional (2D) materials consisting of heavy atoms with particular arrangements may host exotic quantum properties. Here, we report a unique 2D semiconducting binary compound, a Sn_{2}Bi atomic layer on Si(111), in which hexagons are formed by bonding Bi with a triangular network of Sn. Because of the unique honeycomb configuration, the heavy elements, and the energy-dependent hybridization between Sn and Bi, 2D Sn_{2}Bi not only shows strong spin-orbit coupling effects but also exhibits high electron-hole asymmetry: Nearly free hole bands and dispersionless flat electron bands coexist in the same system. By tuning the Fermi level, it is possible to preserve both nearly free and strongly localized charge carriers in the same 2D material, which provides an ideal platform for the studies of strongly correlated phenomena and possible applications in nanodevices.

Mechanochemical synthesis and physico–chemical investigations of new materials for gas sensors

Solid solutions of the InSb-ZnTe semiconductor system containing up to 20 mol.% of ZnTe were synthesized for the first time. The role of mechanochemical treatment in the process of obtaining solid solutions of this system is shown. Solid solutions in the InSb-ZnTe system have been identified by Raman spectroscopy, and the optical properties of its components have been studied. On the basis of an analysis of the anti-stokes spectral radiation distribution the solid solutions formation was identified both on the dependence of the spectral distribution maximum’s shift on the composition of the InSb1-x-ZnTex system, and by estimating the radiation intensity of the initial binary semiconductors at frequencies corresponding to the LO- and TO- vibrations of the binary compounds crystal lattice. The values of the band gap for InSb, (InSb)0.95(ZnTe)0.05 and (InSb)0.9(ZnTe)0.1 were calculated, their values were 0.22 eV, 0.30 eV and 0.38 eV, respectively.

The effect of disorder of small spheres on the photonic properties of the inverse binary NaCl-like structure

Inverse opal structures are experimentally realisable photonic band gap materials. They suffer from the drawback of possessing band gaps that are extremely susceptible to structural disorders. A binary colloidal NaCl lattice, which is also experimentally realisable, is a promising alternative to these opals. In this work, we systematically analyse the effect of structural disorder of the small spheres on the photonic properties of an inverse binary NaCl lattice with a size ratio of 0.30 between the small and large spheres. The types of structural disorders studied include the position of the small spheres in the octahedral void of the large spheres, polydispersity in size of the small spheres, and the fraction of small spheres in the crystal. We find a low susceptibility of the band gap of the inverse NaCl lattice to the disorder of the small spheres.

Photonic Loschmidt echo in binary waveguide lattices.

Time reversal is one of the most intriguing yet elusive wave phenomena of major interest in different areas of classical and quantum physics. Time reversal requires in principle to flip the sign of the Hamiltonian of the system, leading to a revival of the initial state (Loschmidt echo). Here it is shown that Loschmidt echo of photons can be observed in an optical setting without resorting to reversal of the Hamiltonian. We consider photonic propagation in a binary waveguide lattice and show that, by exchanging the two sublattices after some propagation distance, a Loschmidt echo can be observed. Examples of Loschmidt echoes for single photon and NOON states are given in one- and two-dimensional waveguide lattices.