scholarly journals The morphology of an intercalated Au layer with its effect on the Dirac point of graphene

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Amirhossein Bayani ◽  
Karin Larsson
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Dirac Point ◽  
Wide Bandgap ◽  
Point Of View ◽  
Experimental Point ◽  
Functional Theory ◽  
Band Structure Calculations ◽  
Graphene Interface ◽  
Structure Calculations

AbstractThis is a theoretical investigation where Density Functional Theory (DFT) has been used in studying the phenomenon of Au intercalation within the 4H-SiC/graphene interface. The electronic structure of some carefully chosen morphologies of the Au layer has then been of special interest to study. One of these specific Au morphologies is of a more hypothetical nature, whilst the others are, from an experimental point of view, realistic ones. The latter ones were also found to be energetically stable. Band structure calculations showed that intercalated Au layers with morphologies different from a planar Au layer will induce a band gap at the Dirac point of graphene (with up to 174 meV for the morphologies studied in the present work). It should here be mentioned that this bandgap size is four times larger than the energy of thermal motion at room temperature (26 meV). These findings reveal that a wide bandgap at the Dirac point of graphene comes from an inhomogeneous staggered potential on the Au layer, which non-uniformly breaks the sublattice symmetry. The presence of spin-orbit (SO) interactions have also been included in the present study, with the purpose to find out if SO will create a bandgap and/or band splitting of graphene.

Ab Initio Electronic Structure Studies of CuO Multiferroics

2012 ◽  
Vol 488-489 ◽  
pp. 129-132 ◽  
Author(s):  
C. Kanagaraj ◽  
Baskaran Natesan
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Metallic State ◽  
Magnetic Ground State ◽  
Electronic Band ◽  
Functional Theory ◽  
High Tc ◽  
Band Structure Calculations ◽  
Structure Calculations

We have performed detailed structural, electronic and magnetic properties of high - TC multiferroic CuO using first principles density functional theory. The total energy results revealed that AFM is the most stable magnetic ground state of CuO. The DOS and electronic band structure calculations show that in the absence of on-site Coulomb interaction (U), AFM structure of CuO heads to a metallic state. However, upon incorporating U in the calculations, a band gap of 1.2 eV is recovered. Furthermore, the Born effective charges calculated on Cu does not show any anomalous character.This suggests that the polarization seen in CuO could be attributed to the spin induced AFM ordering effect.

Reversible Iodine Intercalation into Tungsten Ditelluride

2020 ◽  
Author(s):  
Patrick Schmidt ◽  
Philipp Schneiderhan ◽  
Markus Ströbele ◽  
Carl P. Romao ◽  
H.-Jürgen Meyer
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Density Wave ◽  
Fused Silica ◽  
Orthorhombic Space Group ◽  
Functional Theory ◽  
Band Structure Calculations ◽  
Axis Length ◽  
A Charge ◽  
Structure Calculations

The new compound WTe2I was prepared by a reaction of WTe2 with iodine in a fused silica vessel at temperatures between 40 and 200 °C. Iodine atoms are intercalated into the van der Waals gap between tungsten ditelluride layers. As a result, the WTe2 layer separation and therefore the c-axis length is significantly increased, and the orthorhombic space group is preserved. Iodine atoms form planar layers between each tungsten ditelluride layer. Due to oxidation by iodine the semi-metallic nature of WTe2 is changed, as shown by comparative band structure calculations for WTe2 and WTe2I based on density functional theory. The calculated phonon band structure of WTe2I suggests a charge density wave instability at low temperature.<br>

Reversible Iodine Intercalation into Tungsten Ditelluride

2020 ◽  
Author(s):  
Patrick Schmidt ◽  
Philipp Schneiderhan ◽  
Markus Ströbele ◽  
Carl P. Romao ◽  
H.-Jürgen Meyer
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Density Wave ◽  
Fused Silica ◽  
Orthorhombic Space Group ◽  
Functional Theory ◽  
Band Structure Calculations ◽  
Axis Length ◽  
A Charge ◽  
Structure Calculations

The new compound WTe2I was prepared by a reaction of WTe2 with iodine in a fused silica vessel at temperatures between 40 and 200 °C. Iodine atoms are intercalated into the van der Waals gap between tungsten ditelluride layers. As a result, the WTe2 layer separation and therefore the c-axis length is significantly increased, and the orthorhombic space group is preserved. Iodine atoms form planar layers between each tungsten ditelluride layer. Due to oxidation by iodine the semi-metallic nature of WTe2 is changed, as shown by comparative band structure calculations for WTe2 and WTe2I based on density functional theory. The calculated phonon band structure of WTe2I suggests a charge density wave instability at low temperature.<br>

scholarly journals Dynamical stability and electronic structure of β-phosphorus carbide nanowires

2021 ◽  
pp. 2050007
Author(s):  
S. A. Shcherbinin ◽  
S. V. Ustiuzhanina ◽  
A. A. Kistanov
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dynamical Stability ◽  
Ab Initio Molecular Dynamics ◽  
Functional Theory ◽  
High Tunability ◽  
Band Structure Calculations ◽  
Molecular Dynamics Calculations ◽  
Unique Shape ◽  
Structure Calculations

In this work, [Formula: see text]-phosphorus carbide 1D nanowires (PCNWs) are investigated in the framework of density functional theory. The dynamical stability of the considered [Formula: see text]-PCNWs at 300[Formula: see text]K is verified using ab initio molecular dynamics calculations. According to the results on the band structure calculations, [Formula: see text]-PCNWs can be semiconductors, semimetals or metals depending on their size and form. Thus, owning to their unique shape and high tunability of electronic properties, [Formula: see text]-PCNWs may be used in optical and photovoltaic nanodevices.

Oxygen adsorption on Ag(110): density functional theory band structure calculations and dynamical simulations

1999 ◽  
Vol 443 (1-2) ◽  
pp. 1-12 ◽  
Author(s):  
Vittoria Isabella Pazzi ◽  
Pierre Herman Theodoor Philipsen ◽  
Evert Jan Baerends ◽  
Gian Franco Tantardini
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Density Functional ◽  
Oxygen Adsorption ◽  
Functional Theory ◽  
Band Structure Calculations ◽  
Dynamical Simulations ◽  
Structure Calculations

Effect of Varying Pnictogen Elements (Pn=N, P, As, Sb, Bi) on the Optoelectronic Properties of SrZn2Pn2

2018 ◽  
Vol 73 (4) ◽  
pp. 285-293 ◽  
Author(s):  
G. Murtaza ◽  
N. Yousaf ◽  
A. Laref ◽  
M. Yaseen
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Structure ◽  
Absorption Coefficient ◽  
Density Functional ◽  
State Of The Art ◽  
Photonic Devices ◽  
Functional Theory ◽  
Band Structure Calculations ◽  
Structure Calculations

AbstractPnictogen-based Zintl compounds have fascinating properties. Nowadays these compounds have gained exceptional interest in thermoelectric and optoelectronic fields. Therefore, in this work the structural, electronic and optical properties of SrZn2Pn2 (Pn=N, P, As, Sb, Bi) compounds were studied using state-of-the-art density functional theory. The optimised lattice parameters (ɑ, c, c/ɑ and bond lengths) are consistent with the experimental results. The bulk moduli and c/a showed a decrease when changing the Pnictogen (Pn) anion from N to Bi in SrZn2Pn2 (Pn=N, P, As, Sb, Bi). The modified Becke-Johnson potential is used for band structure calculations. All compounds show semiconducting behaviour except SrZn2Bi2, which is metallic. Pn-p, Zn-d and Sr-d play an important role in defining the electronic structure of the compounds. The optical conductivity and absorption coefficient strength are high in visible and ultraviolet regions. These band structures and optical properties clearly show that SrZn2Pn2 compounds are potential candidates in the fields of optoelectronic and photonic devices.

scholarly journals Metal-Rich Metallaboranes: Synthesis, Structures and Bonding of Bi- and Trimetallic Open-Faced Cobaltaboranes

Inorganics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 28
Author(s):  
Kriti Pathak ◽  
Chandan Nandi ◽  
Jean-François Halet ◽  
Sundargopal Ghosh
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Room Temperature ◽  
Electron Pair ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Cluster 2 ◽  
Cobalt Center

Synthesis, isolation, and structural characterization of unique metal rich diamagnetic cobaltaborane clusters are reported. They were obtained from reactions of monoborane as well as modified borohydride reagents with cobalt sources. For example, the reaction of [Cp*CoCl]2 with [LiBH4·THF] and subsequent photolysis with excess [BH3·THF] (THF = tetrahydrofuran) at room temperature afforded the 11-vertex tricobaltaborane nido-[(Cp*Co)3B8H10] (1, Cp* = η5-C5Me5). The reaction of Li[BH2S3] with the dicobaltaoctaborane(12) [(Cp*Co)2B6H10] yielded the 10-vertex nido-2,4-[(Cp*Co)2B8H12] cluster (2), extending the library of dicobaltadecaborane(14) analogues. Although cluster 1 adopts a classical 11-vertex-nido-geometry with one cobalt center and four boron atoms forming the open pentagonal face, it disobeys the Polyhedral Skeletal Electron Pair Theory (PSEPT). Compound 2 adopts a perfectly symmetrical 10-vertex-nido framework with a plane of symmetry bisecting the basal boron plane resulting in two {CoB3} units bridged at the base by two boron atoms and possesses the expected electron count. Both compounds were characterized in solution by multinuclear NMR and IR spectroscopies and by mass spectrometry. Single-crystal X-ray diffraction analyses confirmed the structures of the compounds. Additionally, density functional theory (DFT) calculations were performed in order to study and interpret the nature of bonding and electronic structures of these complexes.

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