scholarly journals Effect of Dimensionality on The Electronic Properties of SnSe: A Density Functional Theory Study

2021 ◽  
Vol 32 (2) ◽  
pp. 6-11
Author(s):  
Fatimah Arofiati Noor ◽  
Erik Bhekti Yutomo ◽  
Toto Winata
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Thermoelectric Properties ◽  
Density Functional ◽  
Quantum Confinement Effect ◽  
Dft Method ◽  
Lattice Parameter ◽  
Van Der Waals Interactions ◽  
Generalized Gradient ◽  
Functional Theory

This study investigated the structural and electronic properties of bulk, bilayer, and monolayer SnSe using the density functional theory (DFT) method. We succeeded in calculating the bandgap and identifying accurately the transformation of the band structure from bulk to monolayer systems using generalized gradient approximation. An increase in the lattice parameter a and a decrease in the lattice parameter b were observed when the bulk dimensions were reduced to a monolayer. The reduction of van der Waals interactions when the dimensions of a system are reduced is the main factor that causes changes in lattice parameters. The indirect bandgap of bulk SnSe (0.56 eV, 0.3∆→0.7Σ) becomes wider in the monolayer system (0.94 eV, 0.2∆→0.8Σ). Bandgap widening is predicted due to the emergence of the quantum confinement effect in low-dimensional systems. Furthermore, we found the formation of a quasi-degenerate minimum conduction band in the monolayer SnSe. With the formation of these bands, we predict the monolayer SnSe will have better thermoelectric properties than the bulk or bilayer system. This study provides an in-depth understanding of the electronic structure of SnSe and its correlation to thermoelectric properties.

scholarly journals Density functional theory study of electronic properties of Bi2Se3 and Bi2Te3

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Abdullahi Lawal ◽  
Amiruddin Shaari
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Topological Insulators ◽  
Van Der Waals Interactions ◽  
Partial Density ◽  
Total Density ◽  
Density Of State ◽  
Generalized Gradient ◽  
Linear Dispersion ◽  
Functional Theory

Topological insulators are layered materials via van der Waals interactions with hexagonal unit cell similar to that of graphene. The exciting features of Bi2Se3 and Bi2Te3 topological insulators their zero band gap surface states exhibiting linear dispersion at the Fermi energy. We present here first principles study pertaining to electronics properties of Bi2Se3 and Bi2Te3 compound with and without spin-orbit interaction using density functional theory (DFT). Total density of state (DOS), partial density of state (PDOS) and band structure where determined by Quantum-Espresso simulation package which uses plane wave basis and pseudopotential for the core electrons, while treating exchange-correlation potential with generalized gradient approximation (GGA). From our computations, the obtained results were found to be consistent with the available experimental results. 

scholarly journals Analysis on the energetics, magnetism and electronic properties in a 45° ZnO grain boundary doped with Gd

RSC Advances ◽  
2018 ◽  
Vol 8 (25) ◽  
pp. 13850-13856 ◽  
Author(s):  
Assa Aravindh Sasikala Devi ◽  
Iman S. Roqan
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Grain Boundary ◽  
Electronic Properties ◽  
Single Crystals ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Hubbard Parameter

The structural stability and magnetic properties of a grain boundary (GB) formed by two ZnO single crystals oriented at 45° is investigated by density functional theory, using generalized gradient approximation (GGA) with Hubbard parameter (U).

Crystal Structure of L6, L4-8, L3-12 and L4-6-12 Graphene Polymorphs

2016 ◽  
Vol 845 ◽  
pp. 247-250
Author(s):  
A.E. Kochengin ◽  
Evgeniy A. Belenkov
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Graphene Layers

Calculations of the structure and electronic properties of crystals composed of graphene layers L6, L4-8, L3-12 and L4-6-12 were performed within the framework of density functional theory (DFT) with generalized gradient approximations (GGA). It was found out, that crystals of the four main types of graphene are to have metallic properties.

Tuning of the gold work function by carborane films studied using density functional theory

2019 ◽  
Vol 21 (11) ◽  
pp. 6178-6185 ◽  
Author(s):  
Martin Hladík ◽  
Aliaksei Vetushka ◽  
Antonín Fejfar ◽  
Héctor Vázquez
Keyword(s):  
Density Functional Theory ◽  
Work Function ◽  
Electronic Properties ◽  
Density Functional ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Functional Theory

Using density functional theory including van der Waals interactions, we calculate the adsorption and electronic properties of dithiol-dicarba-closo-dodecaboranes chemisorbed on Au(111) surfaces.

scholarly journals First Principle Study of the Attachment of Graphene onto Different Terminated Diamond (111) Surfaces

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
S. Zhao ◽  
K. Larsson
Keyword(s):  
Density Functional ◽  
Dft Method ◽  
Adhesion Energy ◽  
Van Der Waals Interactions ◽  
Diamond Surface ◽  
Graphene Monolayer ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Aromatic Character ◽  
Finite Band

The adhesion of a graphene monolayer onto terminated or 2x1-reconstructed diamond (111) surfaces has in the present study been theoretically investigated by using a Density Functional Theory (DFT) method. H, F, O, and OH species were used for the surface termination. The generalized gradient spin density approximation (GG(S)A) with the semiempirical dispersion corrections were used in the study of the Van der Waals interactions. There is a weaker interfacial bond (only of type Wan-der-Waals interaction) at a distance around 3 Å (from 2.68 to 3.36 Å ) for the interfacial graphene//diamond systems in the present study. The strongest binding of graphene was obtained for the H-terminated surface, with an adhesion energy of -10.6 eV. In contrast, the weakest binding of graphene was obtained for F-termination (with an adhesion energy of -2.9 eV). For all situations in the present study, the graphene layer was found to retain its aromatic character. In spite of this, a certain degree of electron transfer was observed to take place from graphene to Oontop-, Obridge-, and OH-terminated diamond surface. In addition, graphene attached to Oontop-terminated surface showed a finite band gap.

Benefits of Ga, Ge and As substitution in Li2FeSiO4: a first-principles exploration of the structural, electrochemical and capacity properties

2020 ◽  
Vol 22 (26) ◽  
pp. 14712-14719
Author(s):  
Xiaotong Yan ◽  
Yuhua Hou ◽  
Shouhong Zheng ◽  
Youlin Huang ◽  
Wei Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Electrochemical Capacity ◽  
Fe Substitution

Herein, the feasibility of Fe substitution by Ga, Ge and As in Li2FeSiO4 in modulating its structural, mechanical, electrochemical, capacity and electronic properties was systematically studied via first-principles calculations based on density functional theory within the generalized gradient approximation with Hubbard corrections (GGA+U).

scholarly journals Structural, Electronic and Optical properties of the Inorganic Solar Perovskites XPbBr3 (X= Li or Na)

2021 ◽  
Author(s):  
Samira Idrissi ◽  
lahoucine bahmad ◽  
a benyssef
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Density Functional ◽  
Dft Method ◽  
Lattice Parameter ◽  
Band Gap Energy ◽  
Partial Density ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Quantum Espresso

In this paper, we study the structural, electronic and optical properties of the inorganic solar perovskites XPbBr3 (X= Li or Na). We applied the two methods: the density functional theory (DFT) and time-dependent density-functional theory (TDDFT). In fact, we performed the DFT method using the Quantum Espresso package. Also, the total energies of the studied inorganic solar perovskites XPbBr3 (X= Li or Na) have been deduced as a function of the lattice parameter a (Å). The two calculation methods have been carried out under the GGA-PBE and GGA-PBESol approximations. Moreover, the total and partial density of states (DOS) and the band structure of the studied compounds have been presented and discussed for the two cases: with and without the spin orbit coupling (SOC) approximation. In addition, the DFT and TDDFT have been explored in order to elaborate the structural, the electronic and the optical properties of the inorganic perovskite CsPbI3 material for solar cell applications. When using the GGA-PBESol method without SOC approximation, we found a band gap energy value greater than that one computed when adding the SOC correction. On the other hand, the optical properties of the studied material have been studied. In particular, we found that the inorganic solar Perovskite XPbBr3 (X=Li or Na) materials exhibit a high transparency of the electromagnetic radiations in energy range between 0 eV and 33 eV.

scholarly journals Density Functional Theory Evaluated for Structural and Electronic Properties of 1T-LixTiS2 and Lithium Ion Migration in 1T-Li0.94TiS2

2017 ◽  
Vol 231 (7-8) ◽  
Author(s):  
Vanessa Werth ◽  
Kai Volgmann ◽  
Mazharul M. Islam ◽  
Paul Heitjans ◽  
Thomas Bredow
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Lithium Ion ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Ion Migration ◽  
Generalized Gradient Approximation ◽  
Structural And Electronic Properties ◽  
Weak Chemical

AbstractIn many applications it has been found that the standard generalized gradient approximation (GGA) does not accurately describe weak chemical bond and electronic properties of solids containing transition metals. In this work, we have considered the intercalation material 1T-Li

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