scholarly journals Oblique and Asymmetric Klein Tunneling across Smooth NP Junctions or NPN Junctions in 8-Pmmn Borophene

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1462
Author(s):  
Zhan Kong ◽  
Jian Li ◽  
Yi Zhang ◽  
Shu-Hui Zhang ◽  
Jia-Ji Zhu
Keyword(s):  
Phase Diagram ◽  
Electrical Resistance ◽  
Normal Incidence ◽  
Quantum Structures ◽  
Dirac Fermions ◽  
Two Dimensional ◽  
Dirac Cone ◽  
Klein Tunneling ◽  
Properties Of Materials ◽  
Massless Fermions

The tunneling of electrons and holes in quantum structures plays a crucial role in studying the transport properties of materials and the related devices. 8-Pmmn borophene is a new two-dimensional Dirac material that hosts tilted Dirac cone and chiral, anisotropic massless Dirac fermions. We adopt the transfer matrix method to investigate the Klein tunneling of massless fermions across the smooth NP junctions and NPN junctions of 8-Pmmn borophene. Like the sharp NP junctions of 8-Pmmn borophene, the tilted Dirac cones induce the oblique Klein tunneling. The angle of perfect transmission to the normal incidence is 20.4∘, a constant determined by the Hamiltonian of 8-Pmmn borophene. For the NPN junction, there are branches of the Klein tunneling in the phase diagram. We find that the asymmetric Klein tunneling is induced by the chirality and anisotropy of the carriers. Furthermore, we show the oscillation of electrical resistance related to the Klein tunneling in the NPN junctions. One may analyze the pattern of electrical resistance and verify the existence of asymmetric Klein tunneling experimentally.

Superconductivity in the two-dimensional nonbenzenoid biphenylene sheet with Dirac cone

2D Materials ◽  
2021 ◽  
Author(s):  
Yanfeng Ge ◽  
Zhicui Wang ◽  
Xing Wang ◽  
Wenhui Wan ◽  
Yong Liu
Keyword(s):  
Physical Properties ◽  
Fermi Level ◽  
Superconducting Devices ◽  
Dirac Fermions ◽  
Two Dimensional ◽  
Dirac Cone ◽  
Electronic Density ◽  
Strongly Coupled ◽  
Rotational Vibration ◽  
Electronic Doping

Abstract During the past decade, two-dimensional materials have attracted much attention in superconductivity due to their feasible physical properties and easy chemical modifications. Herein, we use a recently literature reported novel biphenylene sheet (BP sheet) for investigating superconductivity-related physical properties. The electronic states of BP sheet that appeared near the Fermi level are composed of pz orbital of carbon due to sp2 hybridization. Also, an anisotropic Dirac cone is formed just above the Fermi level by crossing two bands comprised of different carbon atoms. One of the two bands is quasi-flat thus leading to a peak of electronic density of states above the Fermi level. In addition, the rotational-vibration phonon mode of the six-membered carbon ring is strongly coupled with electrons. The electron-phonon coupling induces the superconductivity of 6.2 K in BP sheet. Furthermore, both small uniaxial strains and electronic doping can take the Dirac cone and high electronic density of state close to the Fermi level and further raise the superconducting critical temperature to 27.4 K and 21.5 K, respectively. The obtained result suggests that BP sheet with Dirac fermions and superconductivity can be a potential material for the development of future superconducting devices.

Two-dimensional Klein tunneling for massive Dirac fermions with a defined helicity

2020 ◽  
Vol 412 ◽  
pp. 168022 ◽  
Author(s):  
Jorge Navarro-Giraldo ◽  
Carlos Quimbay
Keyword(s):  
Dirac Fermions ◽  
Two Dimensional ◽  
Klein Tunneling

Phase stability of the monolayer Si1-xGex with Dirac cone

Nanoscale ◽  
2021 ◽  
Author(s):  
Xiaoyang Ma ◽  
Tong Yang ◽  
Dechun Li ◽  
Y. P. Feng
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Phase Stability ◽  
Cluster Expansion ◽  
First Principles ◽  
Temperature Phase ◽  
Two Dimensional ◽  
Dirac Cone ◽  
Temperature Phase Diagram

Phase stability and electronic properties of two-dimensional Si1-xGex alloys are investigated via the first-principles method in combination with the cluster expansion and Monte Carlo simulations. The calculated composition-temperature phase diagram...

scholarly journals Mechanical origin of martensite-like structures in two-dimensional ReS2

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Lingli Huang ◽  
Fangyuan Zheng ◽  
Honglin Chen ◽  
Quoc Huy Thi ◽  
Xin Chen ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Two Dimensional ◽  
Domain Formation ◽  
Domain Structures ◽  
And Topology ◽  
Two Dimensional Materials ◽  
Small Lattice ◽  
Properties Of Materials ◽  
Potential Use ◽  
Diffusionless Transformation

AbstractMartensite is a needle-shaped microstructure formed by a rapid, diffusionless transformation and significantly affects the mechanical properties of materials. Here, in two-dimensional ReS2 we show that martensite-like domain structures can form via a diffusionless transformation, involving small lattice deformations. By analyzing the strain distribution and topology of the as-grown chemical vapor deposition samples, we find that cooling-induced strain at the ReS2/substrate interface is responsible for the mechanical loading and is essential for martensite-like domain formation. Meanwhile, the effect of cooling rate, flake size and substrate on the microstructures revealed the mechanical origin of the transformation. The strain-induced lattice reconstructions are rationalized and possibly lead to ferroelastic effects. In view of the strong anisotropy in electronic and optical properties in two dimensional materials like ReS2, opportunities exist for strain-correlated micro/nanostructure engineering, which has potential use in next-generation strain-tunable devices.

Two-Dimensional Honeycomb B2Se with Orthogonal Lattice: High Stability and Strong Anisotropic Dirac Cone

2020 ◽  
Vol 124 (13) ◽  
pp. 7558-7565 ◽  
Author(s):  
Ji-kai Lyu ◽  
Wei-xiao Ji ◽  
Shu-feng Zhang ◽  
Chang-wen Zhang ◽  
Pei-ji Wang
Keyword(s):  
High Stability ◽  
Two Dimensional ◽  
Dirac Cone

scholarly journals NONCOMMUTATIVE GRAPHENE

2013 ◽  
Vol 28 (16) ◽  
pp. 1350064 ◽  
Author(s):  
CATARINA BASTOS ◽  
ORFEU BERTOLAMI ◽  
NUNO COSTA DIAS ◽  
JOÃO NUNO PRATA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Dirac Equation ◽  
Energy Levels ◽  
Dirac Fermions ◽  
Two Dimensional ◽  
Dirac System ◽  
Noncommutative Parameter

We consider a noncommutative description of graphene. This description consists of a Dirac equation for massless Dirac fermions plus noncommutative corrections, which are treated in the presence of an external magnetic field. We argue that, being a two-dimensional Dirac system, graphene is particularly interesting to test noncommutativity. We find that momentum noncommutativity affects the energy levels of graphene and we obtain a bound for the momentum noncommutative parameter.

COMPLEX BIFURCATION STRUCTURES IN THE HINDMARSH–ROSE NEURON MODEL

2007 ◽  
Vol 17 (09) ◽  
pp. 3071-3083 ◽  
Author(s):  
J. M. GONZÀLEZ-MIRANDA
Keyword(s):  
Phase Diagram ◽  
Bifurcation Diagram ◽  
Parameter Space ◽  
Neuron Model ◽  
Two Dimensional ◽  
Dimensional Parameter ◽  
Rapid Responses ◽  
Bifurcation Structures

The results of a study of the bifurcation diagram of the Hindmarsh–Rose neuron model in a two-dimensional parameter space are reported. This diagram shows the existence and extent of complex bifurcation structures that might be useful to understand the mechanisms used by the neurons to encode information and give rapid responses to stimulus. Moreover, the information contained in this phase diagram provides a background to develop our understanding of the dynamics of interacting neurons.

Diffraction of a pulse by a resistive half-plane. I. Normal incidence

1960 ◽  
Vol 255 (1283) ◽  
pp. 538-549 ◽  
Keyword(s):  
Time Dependence ◽  
Half Plane ◽  
Wave Diffraction ◽  
Diffraction Problem ◽  
Normal Incidence ◽  
Step Function ◽  
Two Dimensional ◽  
Dynamic Similarity ◽  
Function Time ◽  
Dimensional Wave

The two-dimensional wave diffraction problem, acoustic or electromagnetic, in which a pulse of step-function time dependence is diffracted by a resistive half-plane is solved by assuming dynamic similarity in the solution.

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