Tuning the half-metallicity in reconstructed CrN (111) surfaces

Hernandez, Juan Carlos Moreno; Ponce‐Pérez, R.; Cocoletzi, Gregorio H.; Yaseen, Zaher Mundher; Takeuchi, Noboru

doi:10.1016/j.surfin.2022.102420

Cited by 6 publications

(10 citation statements)

References 29 publications

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“…The thermodynamic analysis is useful to determine the stability of different structures because it depends only on the chemical potential. Therefore, since we are interested in the thermodynamic stability of the AlP (001) surfaces, in this work we employed the so-called surface formation energy (SFE) formalism, which has been adapted to our system following refs − . To apply the formalism, thermodynamic equilibrium between the bulk and the surface is assumed, which implies that μ Al bulk + μ normalP bulk − normalΔ H normalf AlP = μ AlP bulk = μ Al + μ normalP with μ Al ≤ μ Al bulk and μ normalP ≤ μ normalP bulk where μ i is the chemical potential of the i th species and Δ H f AlP is the heat of formation for the AlP compound.…”

Section: Methodsmentioning

confidence: 99%

Insights about AlP (001) Surface Reconstructions: A Density Functional Theory Study

Sánchez Ovalle,

Martínez-Guerra,

Takeuchi

et al. 2023

ACS Appl. Electron. Mater.

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Using first-principles calculations and thermodynamics criteria, we investigated the structural and electronic properties of the AlP (001) surface. We considered 18 different possible surface reconstructions. They were chosen by considering the stable surfaces reported for other III−V semiconductors. According to the results, five stable surface reconstructions were found: at Al-rich conditions, the (2 × 4) mixed dimer and the δ (2 × 6) surfaces, at intermediate conditions, the δ (2 × 4), and β2 (2 × 4) surface reconstructions, and at P-rich conditions, the (2 × 2) P-dimer. Electronic properties were evaluated by calculating the density of states. The results show that the surfaces have semiconductor behavior, except for the (2 × 2) P-dimer, which is metal. Electron localization function (ELF) line profiles demonstrate the covalent nature of the Al−P and P−P bonds, while the Al−Al interaction is metallic. Our results provide insights into the possible surface reconstructions in the AlP compounds. Also, the results suggest that the surfaces are good candidates to be employed in the development of diluted magnetic semiconductors.

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Section: Methodsmentioning

confidence: 99%

Insights about AlP (001) Surface Reconstructions: A Density Functional Theory Study

Sánchez Ovalle,

Martínez-Guerra,

Takeuchi

et al. 2023

ACS Appl. Electron. Mater.

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“…The total energy criterion is not enough since each V:Mo relationship has different number of atoms and chemical species. Therefore, we must employ the Defect Formation Energy (DFE) formalism [57][58][59][60] which is independent of the number of atoms in the system and only depends on the chemical potentials of the constituent species. Thermodynamic equilibrium is required to apply the formalism, this implies: where, μ i is the chemical potential of the ith species and H f V 4 AlC 3 is the formation enthalpy.…”

Section: Methodsmentioning

confidence: 99%

Theoretical investigation of the MXene precursors MoxV4-xAlC3 (0 ≤ x ≤ 4)

Moreno-Armenta

Guerrero-Sánchez

Gutiérrez-Ojeda

et al. 2023

Sci Rep

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By first-principles total-energy calculations, we investigated the thermodynamic stability of the MAX solid solution MoxV4-xAlC3 in the 0 ≤ x ≤ 4 range. Results evidence that lattice parameter a increases as a function of Mo content, while the c parameter reaches its maximum expansion at x = 2.5. After that, a contraction is noticed. Mo occupies VI sites randomly until the out-of-plane ordered Mo2V2AlC3 alloy is formed. We employed the Defect Formation Energy (DFE) formalism to evaluate the thermodynamic stability of the alloys. Calculations show five stable compounds. At V-rich conditions and from Mo-rich to Mo-moderated conditions, the pristine V4AlC3 MAX is stable. In the region of V-poor conditions, from Mo-rich to Mo-moderated growth conditions, the solid solutions with x = 0.5, 1, and 1.5 and the o-MAX Mo2V2AlC3 are thermodynamically stable. The line profiles of the Electron Localization Function and Bader charge analysis show that the V-C interaction is mainly ionic, while the Mo-C is covalent. Also, the exfoliation energy to obtain a MXene layer is ~ 0.4 eV/Å2. DFE also shows that MXenes exfoliated from the MAX phase with the same Mo content and atomic arrangement are thermodynamically stable. Our results get a deeper atomic scale understanding of the previously reported experimental evidence.

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“…The total energy criterion is not enough since each V:Mo relationship has different number of atoms and chemical species. Therefore, we have to employ the Defect Formation Energy (DFE) formalism [47][48][49][50] which is independent of the number of atoms in the system and only depends on the chemical potentials of the constituent species. Thermodynamic equilibrium is required to apply the formalism, this implies: 1 where, µ i is the chemical potential of the i th species and is the formation enthalpy.…”

Section: Defect Formation Energy Formalismmentioning

confidence: 99%

Theoretical investigation of the MXene precursors MoxV4-x AlC3 (0≤x≤4)

Moreno-Armenta

Guerrero-Sánchez

Gutiérrez-Ojeda

et al. 2022

Preprint

View full text Add to dashboard Cite

By first-principles total-energy calculations, we investigated the thermodynamic stability of the MAX solid solution MoxV4−xAlC3 in the 0 ≤ x ≤ 4 range. Results evidence that lattice parameter a increases as a function of Mo content, while the c parameter reaches its maximum expansion at x = 2.5. After that, a contraction is noticed. Mo occupies VI sites randomly until the out-of-plane ordered Mo2V2AlC3 alloy is formed. We employed the defect formation energy formalism (DFE) to evaluate the thermodynamic stability of the alloys. Calculations show five stable compounds. At V-rich conditions and from Mo-rich to Mo-moderated conditions, the pristine V4AlC3 MAX is stable. In the region of V-poor conditions, from Mo-rich to Mo-moderated growth conditions, the solid solutions with x = 0.5, 1, and 1.5 and the o-MAX Mo2V2AlC3 are thermodynamically stable. The line profiles of the Electron Localization Function and Bader charge analysis show that the V-C interaction is mainly ionic, while the Mo-C is covalent. Also, the exfoliation energy to obtain a MXene layer is ~ 0.4 eV/Å2. DFE also shows that MXenes exfoliated from the MAX phase with the same Mo content and atomic arrangement are thermodynamically stable. Our results get a deeper atomic scale understanding of the experimental evidence by Pinto and coworkers [J. Mater. Chem. A 8 (2020) 8957].

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Tuning the half-metallicity in reconstructed CrN (111) surfaces

Cited by 6 publications

References 29 publications

Insights about AlP (001) Surface Reconstructions: A Density Functional Theory Study

Insights about AlP (001) Surface Reconstructions: A Density Functional Theory Study

Theoretical investigation of the MXene precursors MoxV4-xAlC3 (0 ≤ x ≤ 4)

Theoretical investigation of the MXene precursors MoxV4-x AlC3 (0≤x≤4)

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