Density functional theory study of phase stability, vibrational, and electronic properties of Mo<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>Al<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>C

Reith, D.; Blaas-Schenner, C.; Podloucky, R.

doi:10.1103/physrevb.86.104105

Cited by 11 publications

(14 citation statements)

References 26 publications

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“…25 The preciseness of spin-orbit coupling in the projector augmented wave method has been verified by comparing the VASP results to calculations using the all electron full-potential linearized augmented plane-wave method 26,27 in Ref. 28 and also cross-checked for LaPtSi.…”

Section: Electronic Structurementioning

confidence: 91%

Synthesis, characterization, electronic structure, and phonon properties of the noncentrosymmetric superconductor LaPtSi

et al. 2013

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In the present work we report on the synthesis, crystal structure, and physical properties (resistivity, magnetization, heat capacity) in combination with density functional theory (DFT) calculations of the electronic structure and phonon properties for the intermetallic compound LaPtSi. LaPtSi crystallizes in its own noncentrosymmetric structure type (space group I 4 1 md; a = 0.42502(1) nm and c = 1.4525(5) nm), which is an ordered ternary derivative of the centrosymmetric α-ThSi 2 -structure. The weakly correlated compound LaPtSi (Sommerfeld value γ = 6.5 mJ/molK 2 ) exhibits superconductivity below T c = 3.35 K and appears to be a fully gapped, weakly coupled s-wave BCS superconductor. The experimental observations are supported by DFT calculations which show that, despite a substantial spin-orbit splitting of the Fermi surfaces, a spin-singlet pairing is prevalent.

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Section: Electronic Structurementioning

confidence: 91%

Synthesis, characterization, electronic structure, and phonon properties of the noncentrosymmetric superconductor LaPtSi

et al. 2013

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“…It is only recently that authors have pointed out the importance of considering full DFT-based free energy data at nonzero temperatures instead of those obtained from the energetics in the ground state. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Only few studies on this topic were performed earlier. [22][23][24][25][26][27] In general excitations of electrons, phonons, magnons and other quasi-particles can contribute to the free energy of defects at elevated temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, several authors demonstrated that the effect of phonon excitations must be considered in first-principles calculations of phase diagrams of binary and ternary metallic and non-metallic alloys. [17][18][19]22,27 While in most of the above-mentioned studies vibrational effects were treated within the harmonic or quasi-harmonic approximation anharmonic effects have been considered in a very recent paper. 11 These authors have III and IV deal with the effect of excitations of phonons and electrons on the free formation, migration and binding energy.…”

Section: Introductionmentioning

confidence: 99%

First-principles calculation of defect free energies: General aspects illustrated in the case of bcc Fe

2015

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Modeling of nanostructure evolution in solids requires comprehensive data on the properties of defects such as the vacancy and foreign atoms. Since most processes occur at elevated temperatures not only the energetics of defects in the ground state but also their temperaturedependent free energies must be known. The first-principles calculation of contributions of phonon and electron excitations to free formation, binding, and migration energies of defects is illustrated in the case of bcc-Fe. First of all, the ground state properties of the vacancy, the foreign atoms Cu, Y, Ti, Cr, Mn, Ni, V, Mo, Si, Al, Co, O, and the O-vacancy pair are determined under constant volume (CV) as well as zero pressure (ZP) conditions, and relations between the results of both kinds of calculations are discussed. Second, the phonon contribution to defect free energies is calculated within the harmonic approximation using the equilibrium atomic positions determined in the ground state under CV and ZP conditions. In most cases the ZPbased free formation energy decreases monotonously with temperature, whereas for CV-based data both an increase and a decrease were found. The application of a quasi-harmonic correction to the ZP-based data does not modify this picture significantly. However, the corrected data are valid under zero-pressure conditions at higher temperatures than in the framework of the purely harmonic approach. The difference between CV-and ZP-based data D. Murali, M. Posselt, M. Schiwarth: First-principles calculation of defect free energies… MS#BD12759 2 is mainly due to the volume change of the supercell since the relative arrangement of atoms in the environment of the defects is nearly identical in the two cases. A simple transformation similar to the quasi-harmonic approach is found between the CV-and ZP-based frequencies.Therefore, it is not necessary to calculate these quantities and the corresponding defect free energies separately. In contrast to ground state energetics the CV-and ZP-based defect free energies do not become equal with increasing supercell size. Third, it was found that the contribution of electron excitations to the defect free energy can lead to an additional deviation of the total free energy from the ground state value or can compensate the deviation caused by the phonon contribution. Finally, self-diffusion via the vacancy mechanism is investigated. The ratio of the respective CV-and ZP-based results for the vacancy diffusivity is nearly equal to the reciprocal of that for the equilibrium concentration. This behavior leads to almost identical CV-and ZP-based values for the self-diffusion coefficient. Obviously, this agreement is accidental. The consideration of the temperature dependence of the magnetization yields self-diffusion data in very good agreement with experiments.

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“…Theoretical calculation shows only carbon vacancies could exist, and the Mo and Al sites tend to be fully occupied (Reith et al, 2012). The C content is suggested to be controlled by the synthesis temperature and will influence the superconductivity (Reith et al, 2012). However, samples prepared at different temperatures show quite similar T c s, indicating the high stability of the C confined inside of the Mo cage.…”

Section: Introductionmentioning

confidence: 98%

“…As shown in Figure 1A, the well-established structure of Mo 3 Al 2 C (P4 1 32) can be viewed as four Mo 6 C octahedra interconnected with each other by corner sharing to form a framework while leaving Al atoms to fill the interstices. Theoretical calculation shows only carbon vacancies could exist, and the Mo and Al sites tend to be fully occupied (Reith et al, 2012). The C content is suggested to be controlled by the synthesis temperature and will influence the superconductivity (Reith et al, 2012).…”

Section: Introductionmentioning

confidence: 98%

Anomalous Charge State Evolution and Its Control of Superconductivity in M3Al2C (M = Mo, W)

et al. 2020

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Density functional theory study of phase stability, vibrational, and electronic properties of Mo3Al2C

Cited by 11 publications

References 26 publications

Synthesis, characterization, electronic structure, and phonon properties of the noncentrosymmetric superconductor LaPtSi

Synthesis, characterization, electronic structure, and phonon properties of the noncentrosymmetric superconductor LaPtSi

First-principles calculation of defect free energies: General aspects illustrated in the case of bcc Fe

Anomalous Charge State Evolution and Its Control of Superconductivity in M3Al2C (M = Mo, W)

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