Theoretical study of CaO, CaS and CaSe via first-principles calculations

Salam, Manal M. Abdus

doi:10.1016/j.rinp.2018.07.042

Cited by 33 publications

(7 citation statements)

References 68 publications

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“…The optimised structural parameters are determined by fitting the variations of energies as a function of equilibrium volumes using the empirical Murnaghan equation of state [35]. The computed structural properties such as the lattice constants (a), bulk modules (B) and their pressure derivatives (B') of CaO and Ca 1−x Ti x O at concentrations x = 0.125, 0.25, 0.5 and 0.75 with other theoretical [36][37][38][39] and experimental [40] results are given in Table 1. The lattice constant and the bulk modulus of CaO are close to theoretical values [36] of GGA-WC [30] and appeared to be consistent with the experimental ones [40].…”

Section: Structural Propertiesmentioning

confidence: 99%

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca_1−xTi_xO

Korichi

Doumi

Mokaddem

et al. 2020

Philosophical Magazine

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Section: Structural Propertiesmentioning

confidence: 99%

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca_1−xTi_xO

Korichi

Doumi

Mokaddem

et al. 2020

Philosophical Magazine

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“…Among them, CaM is the most widely used ranging from catalysis to microelectronics. A lot of studies using different ab initio methods have been performed on structural phase transitions, metallization, cohesive and elastic properties at ambient conditions and under high pressure on CaM [23][24][25][26][27][28]. However, the research of phonon transport in CaM is relatively rare.…”

Section: Introductionmentioning

confidence: 99%

Why thermal conductivity of CaO is lower than that of CaS: a study from the perspective of phonon splitting of optical mode

et al. 2020

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Generally speaking, for materials with the same structure, the thermal conductivity is higher for lighter atomic masses. However, we found that the thermal conductivity of CaO is lower than that of CaS, despite the lighter atomic mass of O than S. To uncover the underlying physical mechanisms, the thermal conductivity of CaM (M = O, S, Se, Te) and the corresponding response to strain is investigated by performing first-principles calculations along with the phonon Boltzmann transport equation. For unstrained system, the order of thermal conductivity is CaS > CaO > CaSe > CaTe. This order remains unchanged in the strain range of −2% to 5%. When the compressive strain is larger than 2%, the thermal conductivity of CaO surpasses that of CaS and becomes the highest thermal conductivity material among the four compounds. By analyzing the mode-dependent phonon properties, the phonon lifetime is found to be dominant over other influential factors and leads to the disparate response of thermal conductivity under strain. Moreover, the changing trend of three-phonon scattering phase space is consistent with that of phonon lifetime, which is directly correlated to the phonon frequency gap induced by the LO-TO splitting. The variation of Born effective charge is found to be opposite for CaM. The Born effective charge of CaO decreases with tensile strain increasing, demonstrating stronger charge delocalization and lower ionicity, while the Born effective charges of CaS, CaSe, and CaTe show a dramatic increase. Such variation indicates that the bonding nature can be effectively tuned by external strain, thus affecting the phonon anharmonic properties and thermal conductivity. The difference of bonding nature is further confirmed by the band structure. Our results show that the bonding nature of CaM can be modulated by external strain and leads to disparate strain dependent thermal conductivity.

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“…The variations of total energies as a function of volumes of Ca 1-x Cr x O compounds are fitted by Murnaghan (1944) equation of state to determine the equilibrium structural parameters. Table 1 summarizes the lattice constants, the bulk modules, and their first derivatives with other experimental data (Mammone et al, 1981;Kaneko et al, 1982;Richet et al, 1988) and theoretical values (Tran et al, 2007;Wu et al, 2014;Cinthia et al, Fan et al, 2015;Nejatipour and Dadsetani, 2015;Santana et al, 2016;Yang et al, 2016;Salam, 2018) computed by the generalized gradient approximation of Perdew-Burke-Ernzerhof (GGA-PBE) (Perdew et al, 1996), revised GGA of Perdew-Burke-Ernzerhof (GGA-PBEsol) (Perdew et al, 2008) and the local density approximation (LDA) (Perdew and Zunger, 1981;Perdew and Wang, 1992).…”

Section: Equilibrium Structural Parametersmentioning

confidence: 99%

“…Table 2 shows the computed band gaps such as the direct HMF gaps (Fan et al, 2015;Nejatipour and Dadsetani, 2015;Yang et al, 2016;Tran and Blaha, 2017;Salam, 2018) and experimental data (Whited et al, 1973). The result of wideindirect gap of 5.392 eV of CaO is in good agreement with recent calculated value of 5.35 eV of Tran and Blaha (2017) study using the same TB-mBJ potential (Becke and Johnson, 2006;Tran and Blaha, 2009), and it is better than the values ranging from 3.437 to 3.67 eV of Fan et al (2015), Nejatipour and Dadsetani (2015), Yang et al (2016), Tran and Blaha (2017), Salam (2018) found by the LDA (Perdew and Zunger, 1981;Perdew and Wang, 1992), GGA-WC (Wu and Cohen, 2006), GGA-PBE (Perdew et al, 1996), and GGA-PBEsol exchange potentials (Perdew et al, 2008). The TB-mBJ provides accurate gap for CaO because he is known for its performance in the calculation of electronic structures of insulators and semiconductors with respect to LDA and all forms of GGA approximations (Bhattacharjee and Chattopadhyaya, 2017a,b; Chattopadhyaya and Bhattacharjee, 2017;Berriah et al, 2018).…”

Section: Electronic Propertiesmentioning

confidence: 99%

Recent Insights Into Electronic Performance, Magnetism and Exchange Splittings in the Cr-substituted CaO

Doumi¹,

Mokaddem²,

Tadjer³

et al. 2020

Front. Chem.

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The first-principles computations of density functional theory are employed to characterize the structural properties, electronic structures, and ferromagnetism induced by Cr impurities in Ca 1-x Cr x O compounds at concentrations x = 0. 25, 0.5, and 0.75. The dynamic stability is performed by the phonon spectra calculations. The structural parameters are computed by using Wu-Cohen generalized gradient approximation, while the electronic and magnetic properties are determined by the accurate Tran-Blaha-modified Becke-Johnson exchange potential. The crystal field, direct and indirect exchange splittings were investigated to determine the origin and stability of ferromagnetic state configuration. The Ca 1-x Cr x O systems have right half-metallicities, which are verified by the spin polarization of 100% and the integer values of total magnetic moments. The Ca 0.75 Cr 0.25 O, Ca 0.5 Cr 0.5 O, and Ca 0.25 Cr 0.75 O are half-metallic ferromagnetic with flip-gaps of 1.495, 0.888, and 0.218 eV, respectively. Therefore, the Ca 1-x Cr x O materials are suitable candidates for possible applications of spin-injection in future semiconductors spintronics.

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Theoretical study of CaO, CaS and CaSe via first-principles calculations

Cited by 33 publications

References 68 publications

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca_1−xTi_xO

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca_1−xTi_xO

Why thermal conductivity of CaO is lower than that of CaS: a study from the perspective of phonon splitting of optical mode

Recent Insights Into Electronic Performance, Magnetism and Exchange Splittings in the Cr-substituted CaO

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Theoretical study of CaO, CaS and CaSe via first-principles calculations

Cited by 33 publications

References 68 publications

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca1−xTixO

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca1−xTixO

Why thermal conductivity of CaO is lower than that of CaS: a study from the perspective of phonon splitting of optical mode

Recent Insights Into Electronic Performance, Magnetism and Exchange Splittings in the Cr-substituted CaO

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Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca_1−xTi_xO

Ferromagnetism, half-metallicity and spin-polarised electronic structures characterisation insights in Ca_1−xTi_xO