C-doping Anisotropy Effects on Borophene Electronic Transport

2021 ◽  
Author(s):  
Tadeu Luiz Gomes Cabral ◽  
Lucas Thiago Siqueira De Miranda ◽  
Debora Carvalho de Melo Rodrigues ◽  
Fábio A. L. de Souza ◽  
Wanderla Luis Scopel ◽  
...  
Keyword(s):  
Electronic Transport ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Scanning Tunneling ◽  
Total Density ◽  
Tunneling Microscopy ◽  
Electronic Band ◽  
Zero Bias ◽  
Current Confinement ◽  
C Doping

Abstract The electronic transport anisotropy for different C-doped borophene polymorphs (β12 and χ3) was investigated theoretically combining density functional theory (DFT) and non-equilibrium Green’s function (NEGF). The energetic stability analysis reveals that B atoms replaced by C is more energetically favorable for χ3 phase. We also verify a directional character of the electronic band structure on C-doped borophene for both phases. Simulated Scanning tunneling microscopy (STM) and also total density of charge confirm the directional character of the bonds. The zero bias transmission for β12 phase at E − EF = 0 shows that C-doping induces a local current confinement along the lines of doped sites. The I − V curves show that C-doping leads to an anisotropy amplification in the β12 than in the χ3. The possibility of confining the electronic current at an specific region of the C-doped systems, along with the different adsorption features of the doped sites, poses them as promising candidates to highly sensitive and selective gas sensors.

scholarly journals Ab-initio study of the orthorhombic ndmno3 perovskite

2014 ◽  
Vol 70 (a1) ◽  
pp. C1806-C1806
Author(s):  
Samir Bentata ◽  
Bouabdellah Bouadjemi ◽  
Tayeb Lantri ◽  
Wissem Benstaali
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Total Density ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Ferromagnetic Ground State ◽  
Total Density Of States

We investigate the structural, electronic and magnetic properties of the orthorhombic Perovskite oxyde NdMnO3 through density-functional-theory (DFT) calculations using both generalized gradient approximation GGA+U, where U is on-site Coulomb interaction correction. The electronic band structure, the partial and total density of states (DOS) and the magnetic moment are determined. The results show a half-metallic ferromagnetic ground state for the orthorhombic NdMnO3.

scholarly journals Electronic band structure, optical, dynamical and thermodynamic properties of cesium chloride (CsCl) from first-principles

2015 ◽  
Vol 6 ◽  
pp. A7 ◽  
Author(s):  
Suat Bingol ◽  
Bahattin Erdinc ◽  
Harun Akkus
Keyword(s):  
Thermodynamic Properties ◽  
Band Structure ◽  
Density Of States ◽  
Ground State ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Cesium Chloride ◽  
Total Density ◽  
Electronic Band ◽  
Ground State Properties

The geometric structural optimization, electronic band structure, total density of states for valence electrons, density of states for phonons, optical, dynamical, and thermodynamical features of cesium chloride have been investigated by linearized augmented plane wave method using the density functional theory under the generalized gradient approximation. Ground state properties of cesium chloride are studied. The calculated ground state properties are consistent with experimental results. Calculated band structure indicates that the cesium chloride structure has an indirect band gap value of 5.46 eV and is an insulator. From the obtained phonon spectra, the cesium chloride structure is dynamically stable along the various directions in the Brillouin zone. Temperature dependent thermodynamic properties are studied using the harmonic approximation model.

scholarly journals First-principles study of structural, electronic and magnetic properties of Co-based quaternary Heusler compounds: CoFeCrAl, CoFeTiAs, CoFeCrGa and CoMnVAs

BIBECHANA ◽  
2017 ◽  
Vol 15 ◽  
pp. 50-59 ◽  
Author(s):  
Bikram Pandey ◽  
Ram Babu Ray ◽  
Gopi Chandra Kaphle
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Tight Binding ◽  
Lattice Parameter ◽  
Total Density ◽  
Heusler Compounds ◽  
Electronic Band ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

We study the Structural, Electronic and Magnetic properties of Co-based LiMgPdSn-types of quaternary Heusler compounds (CoFeCrAl, CoFeTiAs, CoFeCrGa, and CoMnVAS) using Density Functional Theory (DFT) implemented on Tight Binding Linear Muffin-Tin Orbital within Atomic Sphere Approximation(TB-LMTO-ASA) Code. The optimized value of lattice parameter for CoFeCrAl, CoFeTiAs, CoFeCrGa and CoMnVAs are found to be 5.61A˚, 5.76 A˚, 5.61A˚ and 5.71A˚ respectively. From the calculation of electronic band structure and spin polarized total density of states (DOS), we found that CoFeCrAl and CoFeCrGa are spin-gapless semiconductor with half-metallic gap of 0.82eV and 0.25eV respectively. CoFeTiAs half-metals (Nearly spin-gapless semiconductor) with half-metallic gap 0.38 eV and CoMnVAs is found to be nearly gapless half-metal. Magnetic moment of these compounds almost obey the Slater-Pauling rules. All these compounds  expected to have high curie temperature which makes them significant for spintroincs/magnetoelectroincs applications.BIBECHANA 15 (2018) 50-59 

scholarly journals Mechanical Deformation and Electronic Structure of a Blue Copper Azurin in a Solid-State Junction

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 506 ◽  
Author(s):  
Carlos Romero-Muñiz ◽  
María Ortega ◽  
J. G. Vilhena ◽  
Ismael Diéz-Pérez ◽  
Juan Carlos Cuevas ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Structural Changes ◽  
Gold Surface ◽  
Scanning Tunneling ◽  
Total Density ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Blue Copper ◽  
Total Density Of States

Protein-based electronics is an emerging field which has attracted considerable attention over the past decade. Here, we present a theoretical study of the formation and electronic structure of a metal-protein-metal junction based on the blue-copper azurin from pseudomonas aeruginosa. We focus on the case in which the protein is adsorbed on a gold surface and is contacted, at the opposite side, to an STM (Scanning Tunneling Microscopy) tip by spontaneous attachment. This has been simulated through a combination of molecular dynamics and density functional theory. We find that the attachment to the tip induces structural changes in the protein which, however, do not affect the overall electronic properties of the protein. Indeed, only changes in certain residues are observed, whereas the electronic structure of the Cu-centered complex remains unaltered, as does the total density of states of the whole protein.

Ab initio calculation on the Optical Properties of AA- Stacked two dimensional Graphene, Silicene, Germanene, and Stanene

2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Complex Refractive Index ◽  
Single Layer ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Wide Range ◽  
Optical Region

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.

First principles calculation of structural, electronic and optical properties of (001) and (110) growth axis (InN)/(GaN)n superlattices

2021 ◽  
Vol 67 (1 Jan-Feb) ◽  
pp. 7
Author(s):  
B. Bachir Bouiadjra ◽  
N. Mehnane ◽  
N. Oukli
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Scale Up ◽  
Energy Scale ◽  
First Principles Calculation ◽  
Full Potential ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Growth Axis

Based on the full potential linear muffin-tin orbitals (FPLMTO) calculation within density functional theory, we systematically investigate the electronic and optical properties of (100) and (110)-oriented (InN)/(GaN)n zinc-blende superlattice with one InN monolayer and with different numbers of GaN monolayers. Specifically, the electronic band structure calculations and their related features, like the absorption coefficient and refractive index of these systems are computed over a wide photon energy scale up to 20 eV. The effect of periodicity layer numbers n on the band gaps and the optical activity of (InN)/(GaN)n SLs in the both  growth axis (001) and (110) are examined and compared. Because of prospective optical aspects of (InN)/(GaN)n such as light-emitting applications, this theoretical study can help the experimental measurements.

scholarly journals Imaging and identification of point defects in PtTe2

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Kuanysh Zhussupbekov ◽  
Lida Ansari ◽  
John B. McManus ◽  
Ainur Zhussupbekova ◽  
Igor V. Shvets ◽  
...  
Keyword(s):  
Point Defects ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Density Functional Theory Calculations ◽  
Charge Carrier Mobility ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Recombination Rates ◽  
And Performance

AbstractThe properties and performance of two-dimensional (2D) materials can be greatly affected by point defects. PtTe2, a 2D material that belongs to the group 10 transition metal dichalcogenides, is a type-II Dirac semimetal, which has gained a lot of attention recently due to its potential for applications in catalysis, photonics, and spintronics. Here, we provide an experimental and theoretical investigation of point defects on and near the surface of PtTe2. Using scanning tunneling microscopy and scanning tunneling spectroscopy (STS) measurements, in combination with first-principle calculations, we identify and characterize five common surface and subsurface point defects. The influence of these defects on the electronic structure of PtTe2 is explored in detail through grid STS measurements and complementary density functional theory calculations. We believe these findings will be of significance to future efforts to engineer point defects in PtTe2, which is an interesting and enticing approach to tune the charge-carrier mobility and electron–hole recombination rates, as well as the site reactivity for catalysis.

scholarly journals Research on Molecular Structure and Electronic Properties of Ln3+ (Ce3+, Tb3+, Pr3+)/Li+ and Eu2+ Co-Doped Sr2Si5N8 via DFT Calculation

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1849
Author(s):  
Ziqian Yin ◽  
Meijuan Li ◽  
Jianwen Zhang ◽  
Qiang Shen
Keyword(s):  
Molecular Structure ◽  
Energy Level ◽  
Density Functional ◽  
Formation Energy ◽  
Electronic Band Structure ◽  
Blue Shift ◽  
Lanthanide Ions ◽  
Partial Replacement ◽  
Electronic Band ◽  
Charge Imbalance

We use density functional theory (DFT) to study the molecular structure and electronic band structure of Sr2Si5N8:Eu2+ doped with trivalent lanthanides (Ln3+ = Ce3+, Tb3+, Pr3+). Li+ was used as a charge compensator for the charge imbalance caused by the partial replacement of Sr2+ by Ln3+. The doping of Ln lanthanide atom causes the structure of Sr2Si5N8 lattice to shrink due to the smaller atomic radius of Ln3+ and Li+ compared to Sr2+. The doped structure’s formation energy indicates that the formation energy of Li+, which is used to compensate for the charge imbalance, is the lowest when the Sr2 site is doped. Thus, a suitable Li+ doping site for double-doped lanthanide ions can be provided. In Sr2Si5N8:Eu2+, the doped Ce3+ can occupy partly the site of Sr12+ ([SrN8]), while Eu2+ accounts for Sr12+ and Sr22+ ([SrN10]). When the Pr3+ ion is selected as the dopant in Sr2Si5N8:Eu2+, Pr3+ and Eu2+ would replace Sr22+ simultaneously. In this theoretical model, the replacement of Sr2+ by Tb3+ cannot exist reasonably. For the electronic structure, the energy level of Sr2Si5N8:Eu2+/Li+ doped with Ce3+ and Pr3+ appears at the bottom of the conduction band or in the forbidden band, which reduces the energy bandgap of Sr2Si5N8. We use DFT+U to adjust the lanthanide ion 4f energy level. The adjusted 4f-CBM of CeSr1LiSr1-Sr2Si5N8 is from 2.42 to 2.85 eV. The energy range of 4f-CBM in PrSr1LiSr1-Sr2Si5N8 is 2.75–2.99 eV and its peak is 2.90 eV; the addition of Ce3+ in EuSr1CeSr1LiSr1 made the 4f energy level of Eu2+ blue shift. The addition of Pr3+ in EuSr2PrSr2LiSr1 makes part of the Eu2+ 4f energy level blue shift. Eu2+ 4f energy level in EuSr2CeSr1LiSr1 is not in the forbidden band, so Eu2+ is not used as the emission center.

scholarly journals Dual role of CO in the stability of subnano Pt clusters at the Fe3O4(001) surface

2016 ◽  
Vol 113 (32) ◽  
pp. 8921-8926 ◽  
Author(s):  
Roland Bliem ◽  
Jessi E. S. van der Hoeven ◽  
Jan Hulva ◽  
Jiri Pavelec ◽  
Oscar Gamba ◽  
...  
Keyword(s):  
Density Functional ◽  
Elevated Temperatures ◽  
Time Lapse ◽  
Dual Role ◽  
Oxidation Catalyst ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Active Metal ◽  
Catalytically Active ◽  
The Stability

Interactions between catalytically active metal particles and reactant gases depend strongly on the particle size, particularly in the subnanometer regime where the addition of just one atom can induce substantial changes in stability, morphology, and reactivity. Here, time-lapse scanning tunneling microscopy (STM) and density functional theory (DFT)-based calculations are used to study how CO exposure affects the stability of Pt adatoms and subnano clusters at the Fe3O4(001) surface, a model CO oxidation catalyst. The results reveal that CO plays a dual role: first, it induces mobility among otherwise stable Pt adatoms through the formation of Pt carbonyls (Pt1–CO), leading to agglomeration into subnano clusters. Second, the presence of the CO stabilizes the smallest clusters against decay at room temperature, significantly modifying the growth kinetics. At elevated temperatures, CO desorption results in a partial redispersion and recovery of the Pt adatom phase.

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