<i>Ab initio</i>calculations of electric-field-induced stress profiles for diamond/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>c</mml:mi><mml:mtext>−</mml:mtext><mml:mi mathvariant="normal">B</mml:mi><mml:mi mathvariant="normal">N</mml:mi></mml:mrow></mml:math>(110) superlattices

Ishibashi, Shoji; Tamura, Tomoyuki; Tanaka, Shingo; Kohyama, Masanori; Terakura, Kiyoyuki

doi:10.1103/physrevb.76.153310

Cited by 106 publications

(88 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this approach, an accurate enough numerical potential for the positron is obtained from, instead of the all-electron density never calculated explicitly within the method, a sum of the core density, pseudovalence charge density, and atom-centered compensation charges of the PAW method (Makkonen, Hakala, and Puska, 2006). Positron lifetimes or momentum densities of annihilating electron-positron pairs have been calculated using PAW implementations based on such modern DFT packages as the quantum materials simulator (QMAS) (Ishibashi, 2004;Ishibashi et al, 2007), Vienna ab initio simulation package (VASP) (Kresse and Hafner, 1993;Kresse andFurthmüller, 1996a, 1996b;Kresse and Joubert, 1999) [see, e.g., Puska, 2005, 2006], and ABINIT (Gonze et al, 2009;Wiktor et al, 2013).…”

Section: F Numerical Approaches For Self-consistent Calculationsmentioning

confidence: 99%

Defect identification in semiconductors with positron annihilation: Experiment and theory

2013

View full text Add to dashboard Cite

Positron annihilation spectroscopy is particularly suitable for studying vacancy-type defects in semiconductors. Combining state-of-the-art experimental and theoretical methods allows for detailed identification of the defects and their chemical surroundings. Also charge states and defect levels in the band gap are accessible. In this review the main experimental and theoretical analysis techniques are described. The usage of these methods is illustrated through examples in technologically important elemental and compound semiconductors. Future challenges include the analysis of noncrystalline materials and of transient defect-related phenomena.

show abstract

Section: F Numerical Approaches For Self-consistent Calculationsmentioning

confidence: 99%

Defect identification in semiconductors with positron annihilation: Experiment and theory

2013

View full text Add to dashboard Cite

show abstract

“…All the calculations have been performed with our computational code QMAS (Quantum MAterials Simulator) [10,11]. In the conventional scheme, electronic structures and atomic positions are calculated independently of the presence of the positron.…”

Section: Methodsmentioning

confidence: 99%

Two-Component Density Functional Study of Positron-Vacancy Interaction in Metals and Semiconductors

Ishibashi¹

2017

Acta Phys. Pol. A

View full text Add to dashboard Cite

The positron-vacancy interaction in metals and semiconductors has been studied by the two-component density-functional-theory formalism. If a positron is not trapped at the vacancy, atoms surrounding the vacancy show inward relaxation for most cases except for nitrides, where outward relaxation is observed. The presence of positron suppresses the inward relaxation. Positron lifetimes have been calculated with and without the positron effect. The difference between two lifetime values is investigated in relation to the bulk modulus.

show abstract

“…31 However, there exists an inherent gagedependent problem, namely the non-uniqueness for the choice of the symmetric or asymmetric forms of the kinetic terms in the energy and stress densities, originating from the presence of both forms of the kinetic operator in quantum mechanics. This problem can be settled if the energy and stress densities are integrated within some local region where the differences between the symmetric and asymmetric forms are integrated to zero.…”

Section: Segregation At Grain Boundaries and Local Energy/ Stress Anamentioning

confidence: 99%

Mechanical properties of Fe-rich Si alloy from Hamiltonian

et al. 2017

Self Cite

View full text Add to dashboard Cite

The physical origins of the mechanical properties of Fe-rich Si alloys are investigated by combining electronic structure calculations with statistical mechanics means such as the cluster variation method, molecular dynamics simulation, etc, applied to homogeneous and heterogeneous systems. Firstly, we examined the elastic properties based on electronic structure calculations in a homogeneous system and attributed the physical origin of the loss of ductility with increasing Si content to the combined effects of magneto-volume and D0 3 ordering. As a typical example of a heterogeneity forming a microstructure, we focus on grain boundaries, and segregation behavior of Si atoms is studied through high-precision electronic structure calculations. Two kinds of segregation sites are identified: looser and tighter sites. Depending on the site, different segregation mechanisms are revealed. Finally, the dislocation behavior in the Fe-Si alloy is investigated mainly by molecular dynamics simulations combined with electronic structure calculations. The solid-solution hardening and softening are interpreted in terms of two kinds of energy barriers for kink nucleation and migration on a screw dislocation line. Furthermore, the clue to the peculiar work hardening behavior is discussed based on kinetic Monte Carlo simulations by focusing on the preferential selection of slip planes triggered by kink nucleation.npj Computational Materials (2017) 3:10 ; doi:10.1038/s41524-017-0012-4 INTRODUCTION Mechanical properties of alloys originate from the behavior of electrons and atoms on the microscopic scale; however, the strength of atomic bonding does not directly relate to macroscopic mechanical properties such as the yield strength, fracture toughness, and fatigue resistance. This is because the microstructure on the mesoscale, which is composed of various defects such as impurities, grain boundaries, and dislocations, mediates or enhances the response of alloys against external forces, leading to fairly nonlinear and multiscale phenomena. Facing such a nonlinear nature associated with the strength and plastic deformation of alloys, identifying the controlling factors for the mechanical properties is a significantly difficult task, and clarifying the underlying physics at different length and time scales still remains a major challenge in materials science.The authors of the present article took up the challenge of this complicated problem with their particular theoretical and computational tools unique to each characteristic scale range. These tools are electronic structure calculations, the cluster variation method (CVM) of statistical mechanics, and molecular dynamics (MD) simulations, which may cover the atomic to mesoscopic scale ranges. By virtue of high-performance computers, some of the results obtained by the present calculations achieve a higher precision and reveal a clearer picture than those obtained by ordinary experiments.Among the various mechanical properties, the main focus of the present study is the solid-solut...

show abstract

Ab initiocalculations of electric-field-induced stress profiles for diamond/c−BN(110) superlattices

Cited by 106 publications

References 16 publications

Defect identification in semiconductors with positron annihilation: Experiment and theory

Defect identification in semiconductors with positron annihilation: Experiment and theory

Two-Component Density Functional Study of Positron-Vacancy Interaction in Metals and Semiconductors

Mechanical properties of Fe-rich Si alloy from Hamiltonian

Contact Info

Product

Resources

About