scholarly journals Stable anisotropic single-layer of ReTe2: a first principles prediction

2020 ◽  
Vol 44 (5) ◽  
pp. 450-457
Author(s):  
Mehmet YAĞMURCUKARDEŞ
Keyword(s):  
Raman Spectrum ◽  
Band Gap ◽  
First Principles ◽  
Anisotropic Material ◽  
Poisson Ratio ◽  
Single Layer ◽  
Mechanical Parameters ◽  
Lattice Orientation ◽  
Layer Form ◽  
Distorted Phase

In order to investigate the structural, vibrational, electronic, and mechanical features of single-layer ReTe2first-principles calculations are performed. Dynamical stability analyses reveal that single-layer ReTe2crystallize in adistorted phase while its 1H and 1T phases are dynamically unstable. Raman spectrum calculations show that single-layer distorted phase of ReTe2exhibits 18 Raman peaks similar to those of ReS2and ReSe2. Electronically, single-layerReTe2is shown to be an indirect gap semiconductor with a suitable band gap for optoelectronic applications. In addition,it is found that the formation of Re-units in the crystal induces anisotropic mechanical parameters. The in-plane stiffnessand Poisson ratio are shown to be significantly dependent on the lattice orientation. Our findings indicate that single-layer form of ReTe2can only crystallize in a dynamically stable distorted phase formed by the Re-units. Single-layer ofdistorted ReTe2can be a potential in-plane anisotropic material for various nanotechnology applications.

scholarly journals Ab Initio Study of the Electronic, Vibrational, and Mechanical Properties of the Magnesium Diboride Monolayer

2019 ◽  
Vol 4 (2) ◽  
pp. 37 ◽  
Author(s):  
Jelena Pešić ◽  
Igor Popov ◽  
Andrijana Šolajić ◽  
Vladimir Damljanović ◽  
Kurt Hingerl ◽  
...  
Keyword(s):  
Ab Initio ◽  
First Principles ◽  
Materials Science ◽  
Magnesium Diboride ◽  
Poisson Ratio ◽  
Single Layer ◽  
First Principles Calculations ◽  
Significant Interest ◽  
Science Community ◽  
Fundamental Research

Magnesium diboride gained significant interest in the materials science community after the discovery of its superconductivity, with an unusually high critical temperature of 39 K. Many aspects of the electronic properties and superconductivity of bulk MgB 2 and thin sheets of MgB 2 have been determined; however, a single layer of MgB 2 has not yet been fully theoretically investigated. Here, we present a detailed study of the structural, electronic, vibrational, and elastic properties of monolayer MgB 2 , based on ab initio methods. First-principles calculations reveal the importance of reduction of dimensionality on the properties of MgB 2 and thoroughly describe the properties of this novel 2D material. The presence of a negative Poisson ratio, higher density of states at the Fermi level, and a good dynamic stability under strain make the MgB 2 monolayer a prominent material, both for fundamental research and application studies.

Effect of Impurity Content on Elastic Modulus and Poisson Ratio of Salt Rock

2012 ◽  
Vol 204-208 ◽  
pp. 467-470
Author(s):  
Xian Lei Zong ◽  
Chun He Yang ◽  
Jiang Jiang Zuo ◽  
Jing Bin Xu ◽  
Guo Dong Ji
Keyword(s):  
Elastic Modulus ◽  
Poisson Ratio ◽  
Impurity Content ◽  
Single Layer ◽  
Confining Pressure ◽  
Mechanical Parameters ◽  
Salt Rock ◽  
Estimation Formula ◽  
Experimental Values ◽  
Basic Features

The basic features of salt rock in China are as follows: thickness single layer, more layered distribution and impurities and others. The unstable mechanical parameters are caused by the different types and content of minerals in natural salt rock. Elastic modulus and Poisson ratio of natural samples from certain northern area in China which are compressed under different confining pressure is then analysed with the impurity content to get the relationship between them. Comparing the experimental values with the predicted calculated by Mori-Tanaka method, a linear estimation formula is proposed for the prediction of mechanical parameters suitable for practical engineering applications in this area.

scholarly journals A first-principles study of the relationship between modulus and ideal strength of single-layer, transition metal dichalcogenides

2021 ◽  
Author(s):  
Hao Sun ◽  
Pratyaksh Agrawal ◽  
Chandra Veer Singh
Keyword(s):  
Transition Metal ◽  
Band Gap ◽  
First Principles ◽  
Transition Metal Dichalcogenides ◽  
Single Layer ◽  
Ideal Strength ◽  
Layer Transition ◽  
Metal Dichalcogenides ◽  
The Relationship ◽  
The Ideal

Deformation of single-layer transition metal dichalcogenides (TMDs) can tune their band gap. The regulating range of the band gap is determined by the ideal strengths, which is usually estimated, according...

scholarly journals First-Principles Study on the Effect of Strain on Single-Layer Molybdenum Disulfide

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3127
Author(s):  
Chen Chong ◽  
Hongxia Liu ◽  
Shulong Wang ◽  
Kun Yang
Keyword(s):  
Band Gap ◽  
Molybdenum Disulfide ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Single Layer ◽  
Small Strain ◽  
Structure Changes ◽  
Calculation Results ◽  
Indirect Band Gap

By adopting the first-principles plane wave pseudopotential method based on density functional theory, the electronic structure properties of single-layer MoS2 (molybdenum disulfide) crystals under biaxial strain are studied. The calculation results in this paper show that when a small strain is applied to a single-layer MoS2, its band structure changes from a direct band gap to an indirect band gap. As the strain increases, the energy band still maintains the characteristics of the indirect band gap, and the band gap shows a linear downward trend. Through further analysis of the density of states, sub-orbital density of states, thermodynamic parameters and Raman spectroscopy, it revealed the variation of single-layer MoS2 with strain. This provides a theoretical basis for realizing the strain regulation of MoS2.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

scholarly journals Electronic and optical properties of vacancy ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; and X = Cl, Br, I): a first principles study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Faizan ◽  
K. C. Bhamu ◽  
Ghulam Murtaza ◽  
Xin He ◽  
Neeraj Kulhari ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Dielectric Constants ◽  
Maximum Efficiency ◽  
Exchange Potential ◽  
Double Perovskites ◽  
Electronic And Optical Properties

AbstractThe highly successful PBE functional and the modified Becke–Johnson exchange potential were used to calculate the structural, electronic, and optical properties of the vacancy-ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; X = Cl, Br, and I) using the density functional theory, a first principles approach. The convex hull approach was used to check the thermodynamic stability of the compounds. The calculated parameters (lattice constants, band gap, and bond lengths) are in tune with the available experimental and theoretical results. The compounds, Rb2PdBr6 and Cs2PtI6, exhibit band gaps within the optimal range of 0.9–1.6 eV, required for the single-junction photovoltaic applications. The photovoltaic efficiency of the studied materials was assessed using the spectroscopic-limited-maximum-efficiency (SLME) metric as well as the optical properties. The ideal band gap, high dielectric constants, and optimum light absorption of these perovskites make them suitable for high performance single and multi-junction perovskite solar cells.

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