scholarly journals First-principles calculations of hyperfine interaction, binding energy, and quadrupole coupling for shallow donors in silicon

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Michael W. Swift ◽  
Hartwin Peelaers ◽  
Sai Mu ◽  
John J. L. Morton ◽  
Chris G. Van de Walle
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Predictive Power ◽  
Shallow Donor ◽  
Binding Energies ◽  
Functional Theory ◽  
Shallow Donors ◽  
Quadrupole Coupling ◽  
Underlying Mechanisms ◽  
Donor Charge

AbstractSpin qubits based on shallow donors in silicon are a promising quantum information technology with enormous potential scalability due to the existence of robust silicon-processing infrastructure. However, the most accurate theories of donor electronic structure lack predictive power because of their reliance on empirical fitting parameters, while predictive ab initio methods have so far been lacking in accuracy due to size of the donor wavefunction compared to typical simulation cells. We show that density functional theory with hybrid and traditional functionals working in tandem can bridge this gap. Our first-principles approach allows remarkable accuracy in binding energies (67 meV for bismuth and 54 meV for arsenic) without the use of empirical fitting. We also obtain reasonable hyperfine parameters (1263 MHz for Bi and 133 MHz for As) and superhyperfine parameters. We demonstrate the importance of a predictive model by showing that hydrostatic strain has much larger effect on the hyperfine structure than predicted by effective mass theory, and by elucidating the underlying mechanisms through symmetry analysis of the shallow donor charge density.

First-Principles Analysis on Interaction between Dopant (Ga, Sb) and Contamination Metal Atoms in Ge Crystals

2013 ◽  
Vol 205-206 ◽  
pp. 417-421
Author(s):  
Tatsunori Yamato ◽  
Koji Sueoka ◽  
Takahiro Maeta
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Functional Theory ◽  
Substitutional Site ◽  
Metal Impurities ◽  
Metal Atoms ◽  
Total Energies ◽  
Group 3

The lowest energetic configurations of metal impurities in 4throw (Sc - Zn), 5throw (Y - Cd) and 6throw (Hf - Hg) elements in Ge crystals were determined with density functional theory calculations. It was found that the substitutional site is the lowest energetic configuration for most of the calculated metals in Ge. The most stable configurations of dopant (Ga, Sb) - metal complexes in Ge crystals were also investigated. Following results were obtained. (1) For Ga dopant, 1st neighbor T-site is the most stable for metals in group 3 to 7 elements while substitutional site next to Ga atom is the most stable for metals in group 8 to 12 elements. (2) For Sb dopant, substitutional site next to Sb atom is the most stable for all calculated metals. Binding energies of the interstitial metalMiwith the substitutional dopantDswere obtained by the calculated total energies. The calculated results for Ge were compared with those for Si.

First-principles study of the effect of lanthanum on the niobium diffusion in fcc Fe

2016 ◽  
Vol 30 (23) ◽  
pp. 1650157
Author(s):  
Xueyun Gao ◽  
Huiping Ren ◽  
Chunlong Li ◽  
Haiyan Wang ◽  
Huijie Tan
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Transformation Process ◽  
Binding Energies ◽  
Diffusion Activation Energy ◽  
Repulsive Interaction ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
And Migration

The effect of La on the diffusion of Nb in fcc Fe has been investigated using the first-principles calculations based on the density functional theory. The binding energies of Nb–vacancy, La–vacancy and La–Nb pairs have been calculated. The interactions of Nb–vacancy and La–Nb are attractive in 1nn and 2nn configurations (nn: nearest–neighbor). La atom attracts strongly with the 1nn vacancy, but has a weakly repulsive interaction with the 2nn vacancy. We consider four different Nb jumps in the presence of La atom to investigate the Nb diffusion in terms of vacancy formation and migration energy. The results suggest that La increases the diffusion activation energy of Nb in fcc Fe matrix, and is helpful to decelerate the Nb-diffusion-involved phase transformation process.

scholarly journals Adsorption and diffusion characteristics of lithium on hydrogenated α- and β-silicene

2017 ◽  
Vol 8 ◽  
pp. 1742-1748
Author(s):  
Fadil Iyikanat ◽  
Ali Kandemir ◽  
Cihan Bacaksiz ◽  
Hasan Sahin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Energy Surface ◽  
Diffusion Mechanism ◽  
Single Layer ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Functional Theory ◽  
Diffusion Characteristics ◽  
And Diffusion

Using first-principles density functional theory calculations, we investigate adsorption properties and the diffusion mechanism of a Li atom on hydrogenated single-layer α- and β-silicene on a Ag(111) surface. It is found that a Li atom binds strongly on the surfaces of both α- and β-silicene, and it forms an ionic bond through the transfer of charge from the adsorbed atom to the surface. The binding energies of a Li atom on these surfaces are very similar. However, the diffusion barrier of a Li atom on H-α-Si is much higher than that on H-β-Si. The energy surface calculations show that a Li atom does not prefer to bind in the vicinity of the hydrogenated upper-Si atoms. Strong interaction between Li atoms and hydrogenated silicene phases and low diffusion barriers show that α- and β-silicene are promising platforms for Li-storage applications.

scholarly journals First-Principles Design of Rutile Oxide Heterostructures for Oxygen Evolution Reactions

2021 ◽  
Vol 9 ◽  
Author(s):  
Hyeong Yong Lim ◽  
Sung O Park ◽  
Su Hwan Kim ◽  
Gwan Yeong Jung ◽  
Sang Kyu Kwak
Keyword(s):  
Oxygen Evolution ◽  
Transition Metal Oxides ◽  
First Principles ◽  
Density Functional ◽  
Electrode Materials ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Functional Theory ◽  
Oxide Heterostructures

The oxygen evolution reaction (OER) plays a key role in the determination of overall water-splitting rate. Lowering the high overpotential of the OER of transition metal oxides (TMOs), which are used as conventional OER electrocatalysts, has been the focus of many studies. The OER activity of TMOs can be tuned via the strategic formation of a heterostructure with another TMO substrate. We screened 11 rutile-type TMOs (i.e., MO2; M = V, Cr, Mn, Nb, Ru, Rh, Sn, Ta, Os, Ir, and Pt) on a rutile (110) substrate using density functional theory calculations to determine their OER activities. The conventional volcano approach based on simple binding energies of reaction intermediates was implemented; in addition, the electrochemical-step symmetry index was employed to screen heterostructures for use as electrode materials. The results show that RuO2 and IrO2 are the most promising catalysts among all candidates. The scaling results provide insights into the intrinsic properties of the heterostructure as well as materials that can be used to lower the overpotential of the OER.

Lowest Energy Structures and Electronic Properties of Small Molybdenum Clusters

2005 ◽  
Vol 494 ◽  
pp. 79-82 ◽  
Author(s):  
V. Koteski ◽  
Bozidar Cekić ◽  
N. Novaković ◽  
J. Belošević-Čavor
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
First Principles ◽  
Cluster Size ◽  
Density Functional ◽  
Theoretical Data ◽  
Binding Energies ◽  
Functional Theory ◽  
Average Bond

The structural and geometric properties of small Mo clusters are studied by means of first principles density functional theory (DFT) calculations with planewaves and pseudopotentials. The lowest energy structures of Mon (n=2-6) clusters are determined. The evolution of electronic properties with increasing cluster size is discussed. The geometric structure, average bond lengths, and binding energies of the lowest energy isomers are reported and the results are compared with the available experimental and theoretical data.

FIRST PRINCIPLES STUDY OF CYTOSINE ADSORPTION ON GRAPHENE

2009 ◽  
Vol 08 (01n02) ◽  
pp. 5-8 ◽  
Author(s):  
YONG-HUI ZHANG ◽  
KAI-GE ZHOU ◽  
KE-FENG XIE ◽  
CAI-HONG LIU ◽  
HAO-LI ZHANG ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Binding Energies ◽  
Pristine Graphene ◽  
Functional Theory ◽  
Metal Atoms ◽  
Order Of Magnitude ◽  
Doped Graphene ◽  
Co Doped

The adsorption of cytosine on graphene surface is studied using density functional theory with local density approximation. The cytosine is physisorbed onto graphene through π–π interaction, with a binding energy around -0.39 eV. Due to the weak interaction, the electronic properties of graphene show little change upon adsorption. The cytosine/graphene interaction can be strongly enhanced by introducing metal atoms. The binding energies increase to -0.60 and -2.31 eV in the presence of Li and Co atoms, respectively. The transport behavior of an electric sensor based on Co -doped graphene shows a sensitivity one order of magnitude higher than that of a similar device using pristine graphene. This work reveals that the sensitivity of graphene-based bio-sensors could be drastically improved by introducing appropriate metal atoms.

Hydrogen binding energies and electronic structure of Ni–Pd particles: a clue to their special catalytic properties

2015 ◽  
Vol 17 (39) ◽  
pp. 26140-26148 ◽  
Author(s):  
Linn Leppert ◽  
Rhett Kempe ◽  
Stephan Kümmel
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Catalytic Properties ◽  
Binding Energies ◽  
Hydrogen Binding ◽  
Functional Theory

We investigate the electronic structure of nickel–palladium systems with first-principles density functional theory (DFT).

First-Principles Study of N Impurities in SiC Polytypes

1998 ◽  
Vol 510 ◽  
Author(s):  
W. Windl ◽  
A. A. Demkov
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Binding Energies ◽  
Functional Theory ◽  
Native Defects ◽  
High Binding ◽  
Interstitial Defects ◽  
Formation Energies

AbstractWe investigate theoretically the energetics of nitrogen impurities in β-SiC, their geometrical relaxation, and electronic properties. We find that density-functional theory is able to calculate donor-ionization energies accurately once large enough simulation cells are used. For neutral interstitial defects, we find that configurations where N is three-fold coordinated have very low formation energies and high binding energies with the involved native defects. At the same time, such configurations introduce deep levels into the gap which may result in a non-activation of the donor

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

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