Theoretical study of the structural, electronic and dynamical properties of rocksalt ScN and GaN

Duman, S.; Baǧcı, S.; Tütüncü, H. M.; Uğur, G.; Srivastava, G. P.

doi:10.1016/j.diamond.2005.12.003

Cited by 24 publications

(18 citation statements)

References 21 publications

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“…Our calculated phonon spectra of ScN is generally in good agreement with the recently reported phonon band structure and DOS reported by Paudel and Lambrecht [11]. However, the zone center optical frequency v TO (G), calculated by us is 284 cm À1 , which is smaller in magnitude as compared to those reported from infrared reflectivity measurement by Tranvanglini et al [13] (362 cm À1 ) and recently reported theoretical results of Paudel et al [11] (365 cm À1 ), but compare well with that reported by Duman et al [12] (270 cm À1 ) using GGA. The reason for this discrepancy has already been pointed out in Ref.…”

Section: Phonon Propertiessupporting

confidence: 94%

“…On the other hand, the knowledge of complete phonon-dispersion curves (PDC) of any solid is extremely useful to understand several physical properties, such as structural phase transition, thermodynamical stability, transport and thermal expansion, etc. The PDC of ScN have been predicted by Paudel and Lambrecht [11] and Duman et al [12] theoretically and only zone center optical modes [16] using a first-principles linear response method have predicted the lattice vibrations in ScAs and ScSb both at ambient and close to the phase transition pressure, revealing a LA mode softening at the X-point due to high pressure. Although significant progress has been made in the theoretical description of the structural and electronic properties of ScX (X ¼ N, P) compounds at ambient pressure, their elastic, and phonon properties at high pressure are not yet reported.…”

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confidence: 99%

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Ab initio study of structural, electronic, elastic, and phonon properties of ScN and ScP at ambient and high pressure

Pandit

Rakshit

Sanyal

2010

Physica Status Solidi (b)

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The structural, electronic, and elastic properties of ScN and ScP in NaCl (B 1 phase) and CsCl (B 2 phase) structures and the phonon dispersion at ambient and high pressure, close to phase transition, have been investigated by using first-principles pseudopotential method in the framework of density functional theory with the generalized gradient approximation. It is found that both compounds are stable in B 1 phase at ambient pressure and undergo a structural phase transition to B 2 phase at 368.76 and 247.56 GPa, respectively. ScN is a semiconductor and ScP is semimetallic at ambient pressure (B 1 phase), whereas both the compounds are metallic at high pressure (B 2 phase). The calculated lattice parameter (a), bulk modulus (B), and their first-order pressure derivative (B 0 ) are in good agreement with previous calculations. The elastic constants (C 11 , C 12 , and C 44 ) have been calculated in both phases. We also report the phonon structure of these compounds at ambient and close to the phase-transition pressure and compared among themselves. It is shown that their phonon structures are consistent with electronic properties at ambient and high pressures. Near B 1 -B 2 transition, the LA mode at X-point softens considerably leading to structural instability.

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Section: Phonon Propertiessupporting

confidence: 94%

mentioning

confidence: 99%

Ab initio study of structural, electronic, elastic, and phonon properties of ScN and ScP at ambient and high pressure

Pandit

Rakshit

Sanyal

2010

Physica Status Solidi (b)

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“…The equilibrium lattice constants of 4.510 and 4.513 Å obtained for RS-ScN structure by EV ex -PW co -GGA and PBE-GGA calculations, respectively, are found to be very close to the measured values of 4.501 [1] and 4.5 Å [3][4][5][6][7][8]. On the other hand, the equilibrium lattice constant of RS-ScN obtained by the present EV ex -PW co -GGA and PBE-GGA calculations are found to be very close to the values calculated by FP-LAPW and abinitio PP methods within PBE-GGA and PCVJPSF (Perdew-Chevary-Vosko-Jackson-Pederson-Singh-Fiolhais)-GGA [39] schemes [10,12,13]. The present bulk moduli of 202.…”

Section: Methods Of Calculationssupporting

confidence: 68%

A comparative study for structural and electronic properties of single-crystal ScN

Mohammad¹,

Katırcıoğlu²

2011

Condens. Matter Phys.

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A comparative study by FP-LAPW calculations based on DFT within LDA, PBE-GGA, EVex-PWco-GGA, and EVex-GGA-LDAco schemes is introduced for the structural and electronic properties of ScN in RS, ZB, WZ, and CsCl phases. According to all approximations used in this work, the RS phase is the stable ground state structure and makes a transition to CsCl phase at high transition pressure. While PBE-GGA and EVex-PWco-GGA's have provided better structural features such as equilibrium lattice constant and bulk modulus, only EVex-PWco-GGA and EVex-GGA-LDAco's have given the non zero, positive indirect energy gap for RS-ScN, comparable with the experimental ones. The indirect band gap of ScN in RS phase is enlarged to the corresponding measured value by EVex-PWco-GGA+U SIC calculations in which the Coulomb self and exchangecorrelation interactions of the localized d-orbitals of Sc have been corrected by the potential parameter of U. The EVex-PWco-GGA calculations have also provided good results for the structural and electronic features of ScN in ZB, WZ, and CsCl phases comparable with the theoretical data available in the literature. EVex-PWco-GGA and EVex-PWco-GGA+U SIC schemes are considered to be the best ones among the others when the structural and electronic features of ScN are aimed to be calculated by the same exchange-correlation energy approximations.

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“…metallic in nature as found earlier by Srivastava et al26 But such a discrepancy is not surprising as DFT is known to underestimate the band gap. It can be seen that for U = 3.5 eV, we get an indirect ⌫ to X gap of 0.89 eV, direct ⌫ point gap of 2.93 eV, and X point gap of 1.86 eV, values that are reasonably close to experimental observations and other theoretical predictions.…”

mentioning

confidence: 62%

Electronic structure, phonons, and thermal properties of ScN, ZrN, and HfN: A first-principles study

Saha

Acharya

Sands³

et al. 2010

Journal of Applied Physics

131

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With a motivation to understand microscopic aspects of ScN, ZrN, and HfN relevant to the thermoelectric properties of nitride metal/semiconductor superlattices, we determine their electronic structure, vibrational spectra and thermal properties using first-principles calculations based on density functional theory with a generalized gradient approximation of the exchange correlation energy. We find a large energy gap in the phonon dispersions of metallic ZrN and HfN, but a gapless phonon spectrum for ScN spanning the same energy range, this suggests that a reduced thermal conductivity, suitable for thermoelectric applications, should arise in superlattices made with ScN and ZrN or ScN and HfN. To obtain an electronic energy band gap of ScN comparable to experiment, we use a Hubbard correction with a parameter U ͑=3.5 eV͒. Anomalies in the acoustic branches of the phonon dispersion of ZrN and HfN, manifested as dips in the bands, can be understood through the nesting of Fermi surface determined from our calculations. To connect with transport properties, we have determined effective masses of ScN and determined their dependence on the U parameter. Using the relaxation time approximation in the Boltzmann transport theory, we estimate the temperature dependence of the lattice thermal conductivity and discuss the chemical trends among these nitrides.

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Theoretical study of the structural, electronic and dynamical properties of rocksalt ScN and GaN

Cited by 24 publications

References 21 publications

Ab initio study of structural, electronic, elastic, and phonon properties of ScN and ScP at ambient and high pressure

Ab initio study of structural, electronic, elastic, and phonon properties of ScN and ScP at ambient and high pressure

A comparative study for structural and electronic properties of single-crystal ScN

Electronic structure, phonons, and thermal properties of ScN, ZrN, and HfN: A first-principles study

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