scholarly journals Topological Atomic Chains on 2D Hybrid Structure

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3289
Author(s):  
Tomasz Kwapiński ◽  
Marcin Kurzyna
Keyword(s):  
Tight Binding ◽  
Wide Band ◽  
Hybrid Structure ◽  
Spectral Density Function ◽  
Hybrid Structures ◽  
Function Technique ◽  
Edge States ◽  
Surface Singularities ◽  
Atomic Chains ◽  
Topological States

Mid-gap 1D topological states and their electronic properties on different 2D hybrid structures are investigated using the tight binding Hamiltonian and the Green’s function technique. There are considered straight armchair-edge and zig-zag Su–Schrieffer–Heeger (SSH) chains coupled with real 2D electrodes which density of states (DOS) are characterized by the van Hove singularities. In this work, it is shown that such 2D substrates substantially influence topological states end evoke strong asymmetry in their on-site energetic structures, as well as essential modifications of the spectral density function (local DOS) along the chain. In the presence of the surface singularities the SSH topological state is split, or it is strongly localized and becomes dispersionless (tends to the atomic limit). Additionally, in the vicinity of the surface DOS edges this state is asymmetrical and consists of a wide bulk part together with a sharp localized peak in its local DOS structure. Different zig-zag and armachair-edge configurations of the chain show the spatial asymmetry in the chain local DOS; thus, topological edge states at both chain ends can appear for different energies. These new effects cannot be observed for ideal wide band limit electrodes but they concern 1D topological states coupled with real 2D hybrid structures.

scholarly journals Hybrid structures applied to ideals in near-rings

2021 ◽  
Author(s):  
B. Elavarasan ◽  
G. Muhiuddin ◽  
K. Porselvi ◽  
Y. B. Jun
Keyword(s):  
Set Theory ◽  
Fuzzy Set ◽  
Real World ◽  
Rough Set Theory ◽  
Wide Spectrum ◽  
Hybrid Structure ◽  
Soft Set ◽  
Hybrid Structures ◽  
Classical Mathematics ◽  
Classical Means

AbstractHuman endeavours span a wide spectrum of activities which includes solving fascinating problems in the realms of engineering, arts, sciences, medical sciences, social sciences, economics and environment. To solve these problems, classical mathematics methods are insufficient. The real-world problems involve many uncertainties making them difficult to solve by classical means. The researchers world over have established new mathematical theories such as fuzzy set theory and rough set theory in order to model the uncertainties that appear in various fields mentioned above. In the recent days, soft set theory has been developed which offers a novel way of solving real world issues as the issue of setting the membership function does not arise. This comes handy in solving numerous problems and many advancements are being made now-a-days. Jun introduced hybrid structure utilizing the ideas of a fuzzy set and a soft set. It is to be noted that hybrid structures are a speculation of soft set and fuzzy set. In the present work, the notion of hybrid ideals of a near-ring is introduced. Significant work has been carried out to investigate a portion of their significant properties. These notions are characterized and their relations are established furthermore. For a hybrid left (resp., right) ideal, different left (resp., right) ideal structures of near-rings are constructed. Efforts have been undertaken to display the relations between the hybrid product and hybrid intersection. Finally, results based on homomorphic hybrid preimage of a hybrid left (resp., right) ideals are proved.

scholarly journals Photonic Topological States in a Two-Dimensional Gyrotropic Photonic Crystal

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 137 ◽  
Author(s):  
Xiao-Chen Sun ◽  
Cheng He ◽  
Xiao-Ping Liu ◽  
Yi Zou ◽  
Ming-Hui Lu ◽  
...  
Keyword(s):  
Transverse Magnetic ◽  
Quantum Spin ◽  
Necessary Condition ◽  
Complex Conjugate ◽  
Optical Parameters ◽  
Edge States ◽  
Quantum Spin Hall Effect ◽  
Pauli Matrices ◽  
Topological States ◽  
Complete Set

Time-reversal symmetry (TRS) of electrons is associated with an anti-unitary operator with T 2 = − 1 , which induces Kramers degeneracy and plays an important role in realizing the quantum spin Hall effect (QSHE). By contrast, TRS of photons is described by T b 2 = 1 . We point out that due to this difference, TRS is not the necessary condition for the construction of the photonic analogue of the QSHE. Instead, by constructing an artificial pseudo TRS T p with T p 2 = − 1 in a photonic system, one can realize the photonic Kramers degeneracy and a pair of topological protected edge states, a photonic analogue of the QSHE. Specifically, by retrieving the optical parameters of materials with the pseudo TRS, we propose a photonic topological insulator (PTI) utilizing a pair of double-degenerate transverse electric (TE) and transverse magnetic (TM) polarizations to mimic the spin up and down states of the electron. We demonstrate that the unidirectional polarization-dependent transportation of TE and TM edge states can be realized in this system based on computer simulations. For all possible symmetry types, we check the robustness of these topological states by using a complete set of impurities, including three Pauli matrices and one complex conjugate operator. The results show that the PTI is protected by the pseudo TRS T p . In general, an arbitrary pair of optical polarizations on the Bloch sphere can be utilized to construct photonic pseudospin states and the PTI. Our findings confirm the physical meaning of the pseudo TRS and may provide guidance for future PTI designs.

scholarly journals The effect of moiré superstructures on topological edge states in twisted bismuthene homojunctions

2020 ◽  
Vol 6 (23) ◽  
pp. eaba2773 ◽  
Author(s):  
Jian Gou ◽  
Longjuan Kong ◽  
Xiaoyue He ◽  
Yu Li Huang ◽  
Jiatao Sun ◽  
...  
Keyword(s):  
Single Layer ◽  
Scanning Tunneling ◽  
Edge States ◽  
First Principles Calculations ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Spatially Distributed ◽  
Topological States ◽  
Device Applications

Creating and controlling the topological properties of two-dimensional topological insulators is essential for spintronic device applications. Here, we report the successful growth of bismuth homostructure consisting of monolayer bismuthene and single-layer black phosphorus–like Bi (BP-Bi) on the HOPG surface. Combining scanning tunneling microscopy/spectroscopy with noncontact atomic force microscopy, moiré superstructures with twist angles in the bismuth homostructure and the modulation of topological edge states of bismuthene were observed and studied. First-principles calculations reproduced the moiré superlattice and indicated that the structure fluctuation is ascribed to the stacking modes between bismuthene and BP-Bi, which induce spatially distributed interface interactions in the bismuth homostructure. The modulation of topological edge states is directly related to the variation of interlayer interactions. Our results suggest a promising pathway to tailor the topological states through interfacial interactions.

scholarly journals Hybrid Structures Applied to Ideals in BCI-Algebras

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
G. Muhiuddin ◽  
D. Al-Kadi ◽  
A. Mahboob
Keyword(s):  
Hybrid Structure ◽  
Ideal Theory ◽  
Hybrid Structures ◽  
The Ideal

In this paper, the notion of hybrid structure is applied to the ideal theory in BCI-algebras. In fact, we introduce the notions of hybrid p -ideal, hybrid h-ideal, and hybrid a-ideal in BCI-algebras and investigate their related properties. Furthermore, we show that every hybrid p -ideal (or h-ideal or a-ideal) is a hybrid ideal in a BCI-algebra but converse need not be true in general and in support, and we exhibit counter examples for each case. Moreover, we consider characterizations of hybrid p -ideal, hybrid h-ideal, and hybrid a-ideal in BCI-algebras.

scholarly journals Are Superconductivity Mechanisms a Matter for Chemists?

2020 ◽  
Vol 5 (4) ◽  
pp. 67
Author(s):  
Michel Pouchard ◽  
Antoine Villesuzanne
Keyword(s):  
Fermi Level ◽  
Phonon Mode ◽  
Tight Binding ◽  
Superconducting Gap ◽  
Metallic State ◽  
Edge States ◽  
High Tc ◽  
Iron Selenide ◽  
Double Well Potential ◽  
High Tc Cuprates

From a tight-binding approach to the instability of nonbonding electronic states, along a double-well potential, we consider here how the coupling of these states with a phonon mode can open a superconducting gap at the Fermi level. The alternation of broken- and unbroken-symmetry states, along the phonon breathing distortion, induces the mixing of band-edge states on a very short timescale, according to the noncrossing rule of chemists. We show that this mixing may generate cationic and anionic disproportionation. The negative U mechanism is thus justified here, leading to the mixing of occupied and unoccupied pair states, for the opening of a 2Δ superconducting gap. The closeness of broad σ* and narrow π* bands in the vicinity of the Fermi level should favor the superconducting phase over the insulating or metallic state, in agreement with Micnas et al.’s studies. We applied this approach to several families of superconducting materials, i.e., doped strontium titanate, high-TC cuprates and iron selenide.

Optimization Design of Core Thickness of Exterior Frame and Core Hybrid Structures in High-Rise Buildings

2012 ◽  
Vol 166-169 ◽  
pp. 14-18
Author(s):  
Shu Yun Zhang ◽  
Wen Wei Zhao ◽  
Hai Hua Wang
Keyword(s):  
Seismic Response ◽  
Optimization Design ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Optimization Method ◽  
Hybrid Structure ◽  
Hybrid Structures ◽  
Response Analysis ◽  
High Rise ◽  
Core Thickness

Considering core thickness is important issue to performance of exterior frame and core hybrid structure in high-rise buildings, seismic response analysis is conducted by response spectrum method for finite element models with different core thickness. The optimization design of core thickness of hybrid Structures on the basis of the seismic response is studied, the core thicknesses are chosen as design variables, the objective function about core volume is adopted, some specification requirements such as deformation, the ratio of lateral stiffness to gravity, storey shear to gravity, storey shear of exterior frame, axial compression ratio of column and wall limb, bearing capacity of structural member and core construction are regarded as restricting conditions, the optimal mathematical model is established for reflecting integrity dynamic properties of hybrid structure. The ANSYS software is used for optimizing tool, the hybrid structures optimization design are made through different initial values for verifying convergence of optimization method, the optimal result show that the performances of hybrid structure are improved, the internal forces are reduced and the ratios of inner force born by exterior frames are increased in the optimal scheme.

scholarly journals Modulation of Optical and Electrical Characteristics by Laterally Stretching DNAs on CVD-Grown Monolayers of MoS2

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Guru P. Neupane ◽  
Minh Dao Tran ◽  
Hyun Kim ◽  
Jeongyong Kim
Keyword(s):  
Electrical Properties ◽  
Raman Spectra ◽  
Tensile Strain ◽  
Hybrid Structure ◽  
Red Shift ◽  
Electric Mobility ◽  
Hybrid Structures ◽  
Electrical Performance ◽  
Optical And Electrical Properties ◽  
Electrical Characteristics

Monolayer MoS2 (1L-MoS2) is an ideal platform to examine and manipulate two dimensionally confined exciton complexes, which provides a large variety of modulating the optical and electrical properties of 1L-MoS2. Extensive studies of external doping and hybridization exhibit the possibilities of engineering the optical and electrical performance of 1L-MoS2. However, biomodifications of 1L-MoS2 and the characterization and applications of such hybrid structures are rarely reported. In this paper, we present a bio-MoS2 hybrid structure fabricated by laterally stretching strands of DNAs on CVD-grown 1L-MoS2. We observed a strong modification of photoluminescence and Raman spectra with reduced PL intensity and red-shift of PL peak and Raman peaks, which were attributed to electron doping by the DNAs and the presence of tensile strain in 1L-MoS2. Moreover, we observed a significant enhancement of electric mobility in the DNA/1L-MoS2 hybrid compared to that in the pristine 1L-MoS2, which may have been caused by the induced strain in 1L-MoS2.

QUANTUM DEVICES WITH MULTIPOLE-ELECTRODE — HETEROJUNCTIONS HYBRID STRUCTURES

2002 ◽  
Vol 12 (04) ◽  
pp. 1159-1171
Author(s):  
RAPHAEL TSU
Keyword(s):  
Quantum Wells ◽  
Quantum Confinement ◽  
Field Effect Transistors ◽  
Inversion Layer ◽  
Quantum Hall ◽  
Hybrid Structure ◽  
Hybrid Structures ◽  
Double Gate ◽  
Quantum Devices ◽  
Quantum Well Structures

Since the introduction of the man-made superlattices and quantum well structures, the field has taken off and developed into Quantum Slab, QS; Quantum Wire, QW; Quantum Dot, QD; and Nanoelectronics. This rapidly expanding field owes its success to the development of epitaxially grown heterojunctions and heterostructures to confine carriers in injection lasers. Meanwhile, the advancement of lithography allows potentials to be applied in nanoscale dimension leading to the possibility of quantum confinement without heterostructures. Actually, quantum states in the inversion layer of field effect transistors, FETs, formed by the application of a large gate voltage appeared several years before the introduction of the superlattices and quantum wells. The quantum Hall effect was first discovered in the Si inversion layer. This chapter, Multipole-Electrode Heterojunction Hybrid Structure, MEHHS, discusses hybrid structures of heterojunctions and applied potentials via multipole-electrodes for a much wider variety of structures for future quantum devices. The technology required to fabricate these electrodes, to some degree, is routinely used in the double-gate devices. Few specific examples are detailed here, hopefully, to stimulate a rapid adoption of a hybrid system for the formation of quasi-discrete states for quantum devices.

Anisotropic terahertz response of stretch-aligned composite films based on carbon nanotube–SiC hybrid structures

RSC Advances ◽  
2015 ◽  
Vol 5 (34) ◽  
pp. 26985-26990 ◽  
Author(s):  
Ruili Wu ◽  
Weilong Li ◽  
Yun Wan ◽  
Zhaoyu Ren ◽  
Xinlong Xu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Composite Films ◽  
Hybrid Structure ◽  
Hybrid Structures

Anisotropic terahertz response of stretch-aligned composite films based on carbon nanotube–SiC hybrid structure was investigated.

Electronic Structure and Surface Properties of SrBi2Ta2O9 and Related Oxides

1997 ◽  
Vol 493 ◽  
Author(s):  
J Robertson ◽  
C W Chen
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Conduction Band ◽  
Tight Binding ◽  
Schottky Barriers ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Edge States ◽  
Tight Binding Method ◽  
S States

ABSTRACTThe electronic structure of SrBi2Ta2O9 and related oxides such as SrBi2Nb2O9, Bi2WO6 and Bi3Ti4O12 have been calculated by the tight-binding method. In each case, the band gap is about 4.1 eV and the band edge states occur on the Bi-O layers and consist of mixed O p/Bi s states at the top of the valence band and Bi p states at the bottom of the conduction band. The main difference between the compounds is that Nb 5d and Ti 4d states in the Nb and Ti compounds lie lower than the Ta 6d states in the conduction band. The surface pinning levels are found to pin Schottky barriers 0.8 eV below the conduction band edge.

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