Optical properties of two-dimensional materials with tilted anisotropic Dirac cones: theoretical modelling with application to doped 8-Pmmn borophene

2021 ◽  
Author(s):  
Vl A Margulis ◽  
E E Muryumin
Keyword(s):  
Electronic Band Structure ◽  
Grazing Incidence ◽  
Dielectric Substrate ◽  
Incident Radiation ◽  
Brewster Angle ◽  
Theoretical Modelling ◽  
Two Dimensional ◽  
Electronic Band ◽  
A Value ◽  
Transmission And Absorption

Abstract The optical reflection, transmission and absorption properties of borophene, a newly discovered two-dimensional material with tilted anisotropic Dirac cones, are explored within a simple electronic band structure model of 8-Pmmn borophene, proposed by Zabolotskiy and Lozovik (2016 Phys. Rev. B 94 165403). It is assumed that the borophene layer is deposited on a dielectric substrate, such as Al2O3, and that the borophene's electron density is controlled by an external gate voltage. The reflectance, transmittance and absorbance of the borophene layer, the conduction band of which is filled with electrons up to the Fermi level, are calculated against the frequency of the incident radiation, as well as on the angle of its incidence on the layer. Considered are the two principal cases of the incident radiation polarization either parallel to or normal to the plane of incidence. We reveal that the optical characteristics of 8-Pmmn borophene are distinctly different for the above two cases at all angles of radiation incidence, excepting the grazing incidence, for which the borophene layer is found to behave like a mirror regardless of the wave polarization. The results obtained indicate the possibility of visualizing the borophene layer deposited on a dielectric substrate by observing the minimum reflectivity of this layer at a certain angle incidence (called the quasi-Brewster angle) of the p-polarized radiation, which may differ by a value of about ten degrees from the Brewster angle of the substrate.

FIRST PRINCIPLE CALCULATION OF ELECTRONIC BAND STRUCTURE AND OPTICAL PROPERTIES OF KIO3

2009 ◽  
Vol 23 (10) ◽  
pp. 2405-2412
Author(s):  
HARUN AKKUS ◽  
BAHATTIN ERDINC
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Functional Methods ◽  
A Value ◽  
Direct Band

The electronic band structure and optical properties of the ferroelectric single crystal KIO 3 have been investigated using the density functional methods. The calculated band structure for KIO 3 evidences that the crystal has a direct band gap with a value of 2.83 eV. The structural optimization has been performed. The real and imaginary parts of dielectric function, energy-loss function for volume and surface, and refractive index are calculated along the crystallographic axes.

scholarly journals A First-Principles Study of Nonlinear Elastic Behavior and Anisotropic Electronic Properties of Two-Dimensional HfS2

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 446
Author(s):  
Mahdi Faghihnasiri ◽  
Aidin Ahmadi ◽  
Samaneh Alvankar Golpayegan ◽  
Saeideh Garosi Sharifabadi ◽  
Ali Ramazani
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Electronic Band Structure ◽  
Hexagonal Phase ◽  
Strain Engineering ◽  
Elastic Behavior ◽  
Potential Candidate ◽  
Two Dimensional ◽  
Electronic Band ◽  
Wide Range

We utilize first principles calculations to investigate the mechanical properties and strain-dependent electronic band structure of the hexagonal phase of two dimensional (2D) HfS2. We apply three different deformation modes within −10% to 30% range of two uniaxial (D1, D2) and one biaxial (D3) strains along x, y, and x-y directions, respectively. The harmonic regions are identified in each deformation mode. The ultimate stress for D1, D2, and D3 deformations is obtained as 0.037, 0.038 and 0.044 (eV/Ang3), respectively. Additionally, the ultimate strain for D1, D2, and D3 deformation is obtained as 17.2, 17.51, and 21.17 (eV/Ang3), respectively. In the next step, we determine the second-, third-, and fourth-order elastic constants and the electronic properties of both unstrained and strained HfS2 monolayers are investigated. Our findings reveal that the unstrained HfS2 monolayer is a semiconductor with an indirect bandgap of 1.12 eV. We then tune the bandgap of HfS2 with strain engineering. Our findings reveal how to tune and control the electronic properties of HfS2 monolayer with strain engineering, and make it a potential candidate for a wide range of applications including photovoltaics, electronics and optoelectronics.

scholarly journals Spin Direction-Controlled Electronic Band Structure in Two-Dimensional Ferromagnetic CrI3

Nano Letters ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 3844-3849 ◽  
Author(s):  
Peiheng Jiang ◽  
Lei Li ◽  
Zhaoliang Liao ◽  
Y. X. Zhao ◽  
Zhicheng Zhong
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Two Dimensional ◽  
Electronic Band ◽  
Spin Direction

scholarly journals Two Dimensional β-InSe with Layer-Dependent Properties: Band Alignment, Work Function and Optical Properties

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 82 ◽  
Author(s):  
David K. Sang ◽  
Huide Wang ◽  
Meng Qiu ◽  
Rui Cao ◽  
Zhinan Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Work Function ◽  
High Performance ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Strong Dependence ◽  
Band Alignment ◽  
Thickness Variation ◽  
Two Dimensional ◽  
Electronic Band

Density functional theory calculations of the layer (L)-dependent electronic band structure, work function and optical properties of β-InSe have been reported. Owing to the quantum size effects (QSEs) in β-InSe, the band structures exhibit direct-to-indirect transitions from bulk β-InSe to few-layer β-InSe. The work functions decrease monotonically from 5.22 eV (1 L) to 5.0 eV (6 L) and then remain constant at 4.99 eV for 7 L and 8 L and drop down to 4.77 eV (bulk β-InSe). For optical properties, the imaginary part of the dielectric function has a strong dependence on the thickness variation. Layer control in two-dimensional layered materials provides an effective strategy to modulate the layer-dependent properties which have potential applications in the next-generation high performance electronic and optoelectronic devices.

Piezoelectricity in two-dimensional aluminum, boron and Janus aluminum-boron monochalcogenide monolayers

2021 ◽  
Author(s):  
Saeed Choopani ◽  
Mustafa Menderes Alyoruk
Keyword(s):  
Density Functional ◽  
Piezoelectric Properties ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Piezoelectric Materials ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Two Dimensional ◽  
Electronic Band ◽  
Order Of Magnitude

Abstract Piezoelectricity is a property of a material that converts mechanical energy into electrical energy or vice versa. It is known that group-III monochalcogenides, including GaS, GaSe, and InSe, show piezoelectricity in their monolayer form. Piezoelectric coefficients of these monolayers are the same order of magnitude as the previously discovered two-dimensional (2D) piezoelectric materials such as boron nitride (BN) and molybdenum disulfide (MoS2) monolayers. Considering a series of monolayer monochalcogenide structures including boron and aluminum (MX, M =B, Al, X = O, S, Se, Te), we design a series of derivative Janus structures (AlBX2, X = O, S, Se, Te). Ab-initio density functional theory (DFT) and density functional perturbation theory (DFPT) calculations are carried out systematically to predict their structural, electronic, electromechanical and phonon dispersion properties. The electronic band structure analysis indicate that all these 2D materials are semiconductors. The absence of imaginary phonon frequencies in phonon dispersion curves demonstrate that the systems are dynamically stable. In addition, this study shows that these materials exhibit outstanding piezoelectric properties. For AlBO2 monolayer with the relaxed-ion piezoelectric coefficients, d11=15.89(15.87) pm/V and d31=0.52(0.44) pm/V, the strongest piezoelectric properties were obtained. It has large in-plane and out-of-plane piezoelectric coefficients that are comparable to or larger than those of previously reported non-Janus monolayer structures such as MoS2 and GaSe, and also Janus monolayer structures including: In2SSe, Te2Se, MoSeTe, InSeO, SbTeI, and ZrSTe. These results, together with the fact that a lot of similar 2D systems have been synthesized so far, demonstrate the great potential of these materials in nanoscale electromechanical applications.

scholarly journals Electronic band structure of the two-dimensional metallic electron system Au/Ge(111)

2011 ◽  
Vol 83 (23) ◽  
Author(s):  
P. Höpfner ◽  
J. Schäfer ◽  
A. Fleszar ◽  
S. Meyer ◽  
C. Blumenstein ◽  
...  
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electron System ◽  
Two Dimensional ◽  
Electronic Band
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