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 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.

First-principles study of electronic, dynamical and thermodynamic properties of γ-Li4SiO4

2015 ◽  
Vol 29 (18) ◽  
pp. 1550128 ◽  
Author(s):  
Qiushi Guan ◽  
Tao Gao ◽  
Yanhong Shen ◽  
Shenggui Ma ◽  
Tiecheng Lu ◽  
...  
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
High Symmetry ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Specific Heats ◽  
Indirect Band Gap

We have studied the structural, electronic and dynamic properties of γ- Li4SiO4(lithium orthosilicate) using density functional theory (DFT) with the generalized gradient approximation (GGA). The crystal structure is fully relaxed. The electronic band structure and Density of States (DOS) calculations indicate that γ- Li4SiO4is an insulator with an indirect band gap of 5.19 eV and it has a conduction band with the width of 5.92 eV and two valance bands with the width of 4.45 eV and 0.57 eV, respectively. In the partial DOS, Li and Si electronic densities increase more sharply than O atoms. Comparing with previous works, the phonon dispersion curves without negative frequencies are calculated along high symmetry points. By adding the Born effective charges in the phonon calculation, the LO–TO splittings are also calculated which indicate that γ- Li4SiO4is polar and anisotropic. The optical modes of phonon frequencies at Γ point are assigned as Raman and Infrared-active modes. Additionally, the thermodynamic functions (entropy, internal energy, Helmholtz free energies and constant-volume specific heats) were determined by using the phonon DOS. The calculated results may provide useful guidance of γ- Li4SiO4for future experimental studies in some degree.

A BN analog of two-dimensional triphenylene-graphdiyne: stability and properties

Nanoscale ◽  
2019 ◽  
Vol 11 (18) ◽  
pp. 9000-9007 ◽  
Author(s):  
Imran Muhammad ◽  
Huanhuan Xie ◽  
Umer Younis ◽  
Yu Qie ◽  
Waseem Aftab ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Two Dimensional ◽  
Electronic Band ◽  
Functional Theory ◽  
The Stability ◽  
First Time ◽  
Recent Synthesis

Motivated by the feasibility of hybridizing C- and BN-units as well as the recent synthesis of a triphenylene-graphdiyne (TpG) monolayer, for the first time we explore the stability and electronic band structure of a Tp-BNyne monolayer composed of C-chains and the BN analog of triphenylene (Tp-BNyne) by using density functional theory.

scholarly journals Structural, Electronic, Lattice Dynamic, and Elastic Properties of SnTiO3 and PbTiO3 Using Density Functional Theory

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Shiferaw Kuma ◽  
Menberu Mengesha Woldemariam
Keyword(s):  
Bulk Modulus ◽  
Elastic Properties ◽  
Density Of States ◽  
Elastic Constants ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Theoretical Data ◽  
Modern Theory ◽  
Electronic Band

The structural, electronic, and elastic properties of tetragonal phase of SnTiO3 and PbTiO3 are investigated using first principle calculations. The unknown exchange-correlation functional is approximated with generalized gradient approximation (GGA) as implemented in pseudopotential plane wave approach. The convergence test of total energy with respect to energy cutoff and k-point sampling is preformed to ensure the accuracy of the calculations. The structural properties such as equilibrium lattice constant, equilibrium unit cell volume, bulk modulus, and its derivative are in reasonable agreement with the previous experimental and theoretical works. From elastic constants, mechanical parameters such as anisotropy factor A, shear modulus G, bulk modulus B, Young’s modulus E, and Poison’s ratio n are determined by using Voigt–Reuss–Hill average approximation. In addition, Debye temperature and longitudinal and transversal sound velocities are predicted from elastic constants. The electronic band structure and density of states of both compounds are obtained and compared with the available experimental as well as theoretical data. Born effective charge (BEC), phonon dispersion curve, and density of states are computed from functional perturbation theory (DFPT). Lastly, the spontaneous polarization is determined from the modern theory of polarization, and they are in agreement with the previous findings.

Modulation of the electronic band structure of silicene by polar two-dimensional substrates

2020 ◽  
Vol 22 (37) ◽  
pp. 21412-21420 ◽  
Author(s):  
KaiJuan Pang ◽  
YaDong Wei ◽  
Xiaodong Xu ◽  
WeiQi Li ◽  
JianQun Yang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Two Dimensional ◽  
Electronic Band ◽  
Functional Theory ◽  
Electron Band ◽  
Group Iii ◽  
The Density Functional Theory ◽  
Dirac Electron

Using the density functional theory (DFT) calculations, we find that group-III chalcogenide monolayers can serve as a suitable substrate for silicene, and the Dirac electron band properties of silicene are also fully preserved.

ELECTRONIC AND ELASTIC PROPERTIES OF ZINC-BLENDE MgSe

2013 ◽  
Vol 27 (09) ◽  
pp. 1350027 ◽  
Author(s):  
B. I. ADETUNJI ◽  
P. O. ADEBAMBO ◽  
J. O. AKINLAMI ◽  
G. A. ADEBAYO
Keyword(s):  
Band Structure ◽  
Elastic Properties ◽  
Cohesive Energy ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Density Of State ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Zinc Blende

In the present study, ground state and elastic properties of semiconductor MgSe in zinc-blende phase are investigated using density functional theory (DFT). Exchange-correlation potentials are approximated with the generalized gradient approximation (GGA). From the calculated bulk modulus, we determine the refractive index, plasmon energy, cohesive energy and micro-hardness of the MgSe semiconductor binary alloy. The density of state (DOS), projected density of state (PDOS), phonon dispersion frequencies, charged density, electronic band structure and dielectric functions are also reported. From the band structure, a direct band gap of 2.50 eV was observed in close agreement with other reported calculations, but lower than the experimental value of 3.60 eV. Along the high symmetries directions, we found a striking resemblance between MgSe and a III–V semiconductor, while the high cohesive energy in MgSe suggests filled bonding orbitals which might result in decrease in atomic volume with corresponding increased compression of the s-orbitals under any transition series.

scholarly journals Dynamic, Electronic and Optical Properties of Fm3m-HgF2: A DFT Approach

2021 ◽  
Author(s):  
M VAGHELA ◽  
Dhara Raval ◽  
Bindiya Babariya ◽  
P.N. Gajjar
Keyword(s):  
Band Structure ◽  
Charge Density ◽  
Density Of States ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Random Phase ◽  
Visible Region ◽  
Optical Parameters ◽  
Electronic Band

In the present work, the cubic structure of HgF2 has been studied using generalized gradient approximation within the framework of density functional theory. Here, the positive phonon frequencies in the phonon dispersion curves show stability of the structure. The elastic constants also satisfy criteria of being kinetically stable material. The B/GH ratio 2.56 of HgF2 indicates its ductile nature. The thermodynamic intrinsic parameters of HgF2 have been calculated using linear response method where the temperature variations of Helmholtz free energy (F), internal energy (E), specific heat at constant volume (Cv) and Debay temperature (ϴD) have been studied. The explanation of the bonding nature is discussed using electronic band structure, density of states and charge density. Here, the presence of the wide valence band gap in electronic band structure and density of states displays the ionic behaviors of HgF2. In addition, the charge density along the [111] plane defines hybridization in between ‘s’, ‘p’ and ‘d’ orbitals in HgF2. The optical parameters of Fm3m-HgF2 were calculated using Random Phase Approximation. Here, the found static refractive index is 1.26. The general optical study showing the trend of being transparent in most of the UV region and fully transparent in the visible region by ionic Fm3m HgF2. Also, it shows significant absorption in the entire UV region and a long absorption tail which extends into the visible region.

First-Principles Study of Structural, Electronic, Elastic, Phonon, and Thermodynamical Properties of the Niobium Carbide

2011 ◽  
Vol 171 ◽  
pp. 67-77 ◽  
Author(s):  
Nikita Rathod ◽  
S.D. Gupta ◽  
Sanjeev K. Gupta ◽  
Prafulla K. Jha
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Niobium Carbide ◽  
Electronic Band ◽  
Thermodynamical Properties ◽  
Rocksalt Phase ◽  
The Density Functional Theory

A detailed theoretical study of structural, electronic and vibrational properties of niobium carbide are carried out in rocksalt phase using the density functional theory implemented in ABINIT code. The calculated structural parameters like lattice constant and bulk modulus agree well with the available data. The Zener anisotropy factor (A), Poison's ratio (v), Young’s modulus (Y) and shear modulus (C’) are also presented. The electronic band structure and density of states are presented and discussed in light of bonding nature in NbC. The band structure indicates its metallic nature. The calculated phonon dispersion curves show that the NbC in rocksalt phase has all positive phonons throughout the Brillouin zone. The thermodynamical properties are also presented and discussed.

Effect of Temperature/Pressure on Lattice Dynamics of FeNi

2016 ◽  
Vol 1141 ◽  
pp. 84-90 ◽  
Author(s):  
N.Y. Pandya ◽  
A.D. Mevada ◽  
P.N. Gajjar
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Effect Of Temperature ◽  
Electronic Band ◽  
Functional Theory ◽  
Phonon Dispersion Curves ◽  
Consistent Method ◽  
Hard Ferromagnet

Tetratenite phase of L10 (CuAu) FeNi is identified as a hard ferromagnet in spite of that common FeNi alloys are classified as a soft magnet. Due to its strong magnetic anisotropy and large coercivity, tetrataenite phase of L10 FeNi is under investigation as a rare earth free advanced permanent magnet. Our computed equilibrium lattice constant and c/a ratio for tetratenite phase of L10 (CuAu) FeNi are in 10 % deviation with the other available results. The vibrational and electronic properties of L10 FeNi at finite temperatures/pressures are studied using the first-principles plane wave self-consistent method under the framework of density functional theory. Conclusions based on the phonon dispersion curves, phonon density of states and electronic band structure along with total and projected density of states at finite temperatures/pressures are outlined.

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