Structural and electronic properties of LaN

Ghezali, M.; Amrani, B.; Cherchab, Youcef; Sekkal, Nadir

doi:10.1016/j.matchemphys.2008.06.031

Cited by 22 publications

(28 citation statements)

References 15 publications

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“…[14][15][16][17][18][19] Additionally, this structure type has not been mentioned in the theoretical high-pressure predictions of LaN. 2,3,6,[9][10][11][12] Accordingly, the B1-type structure transforms directly into the CsCl structure type at 25-100 GPa. For BaO, the B2 structure is found to be stable at a pressure of 60.5 GPa.…”

Section: -4mentioning

confidence: 99%

“…In addition, the obtained bulk moduli of ambient LaN do perfectly match the predicted values of 121-173 GPa. 2,3,6,[9][10][11][12] The extrapolated bulk moduli of HP-LaN with values of 278.5(6.4) and 293.2(7.2) GPa are extremely high, ranking HP-LaN as a highly incompressible material comparable to d-ZrN or dHfN having bulk moduli of 285 GPa and 306 GPa, respectively. 38 As expected, the high-pressure phase is less compressible than the ambient phase and shows a smaller first pressure derivative of the bulk modulus.…”

Section: -4mentioning

confidence: 99%

“…225), the high-pressure behavior of this compound attracted remarkable interest over the last few years. 2,3,6,[9][10][11][12] In order to further study the exceptional properties of LaN at high-pressure conditions, pressure-induced structural phase transitions have been investigated theoretically. Thereby, a phase transition into the CsCl-type structure (B2) has been predicted at transition pressures of 25-100 GPa depending on the applied theoretical method.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the compressibility of LaN and an observed high-pressure polymorph, which is isotypic with a high-pressure phase of BaO [14][15][16][17][18][19] and homeotypic with Ph4X (X ¼ Br, I), 20,21 is investigated by a thirdorder Birch-Murnaghan equation of state fitted to the obtained p-V data and compared to the values obtained from an Eulerian strain versus normalized stress F(f)-plot and to predicted values in the literature. 2,3,6,[9][10][11][12] II. EXPERIMENTAL DETAILS A.…”

Section: Introductionmentioning

confidence: 99%

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Reversible high-pressure phase transition in LaN

Schneider¹,

Baumann²,

Salamat³

et al. 2012

Journal of Applied Physics

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In situ high-pressure X-ray powder diffraction experiments on LaN up to 60.1 GPa at ambient temperature in a diamond-anvil cell revealed a reversible, first-order structural phase transition starting at $22.8 GPa and completed at $26.5 GPa from the ambient cubic phase (Fm 3m, no. 225) to a tetragonal high-pressure phase (P4/nmm, no. 19, a ¼ 4.1060(6), c ¼ 3.0446(6) Å , Z ¼ 2, wR p ¼ 0.011), which has not been claimed in theoretical predictions. HP-LaN is isotypic with a high-pressure polymorph of BaO, which crystallizes in a tetragonally distorted CsCl-type structure. The phase transition is accompanied by a volume collapse of about 11% which corresponds well with the reported data on HP-BaO. A linear extrapolation of the c/a ratio of the tetragonally distorted CsCl-type sub-cell reaches a value c/a ¼ 1 of cubic CsCl-type HP-LaN at 91(12) GPa. In addition, the compressibility of LaN was investigated and resulted in a bulk modulus for the ambient pressure phase of

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Section: -4mentioning

confidence: 99%

Section: -4mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reversible high-pressure phase transition in LaN

Schneider¹,

Baumann²,

Salamat³

et al. 2012

Journal of Applied Physics

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Among these, the CeN is most interesting compound due to its unusual physical properties, e.g., anomalously small lattice parameters. 8,9 The anomalous physical properties of this mononitride are attributed to the peculiar behavior of 4f electron of Ce ion.…”

Section: Introductionmentioning

confidence: 99%

On the structural stability of CeN at high pressures: Ab initio calculations

Sahoo¹,

Joshi²,

Gupta³

2013

Journal of Applied Physics

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The structural stability of CeN under hydrostatic compression has been analyzed theoretically. The comparison of enthalpies calculated as a function of hydrostatic compression for rocksalt type (B1), tetragonal (B10), and CsCl type (B2) structures suggests that the B1 phase will transform to B10 structure at $53 GPa, which upon further compression will transform to B2 phase at $200 GPa. However, the static high pressure energy dispersive x-ray diffraction measurements on CeN by Olsen et al. [J. Alloys Compd. 533, 29 (2012)] report that the B1 phase transforms directly to B2 phase at $65 GPa. To resolve the discrepancy between our calculations and experimental results, we have performed lattice dynamic calculations on these structures. The phonon spectra calculated at zero pressure correctly show B1 phase to be dynamically stable, and B10 and B2 to be unstable. At 60 GPa, the B1 phase becomes dynamically unstable and the B10 structure emerges as a dynamically stable phase whereas B2 still remains unstable. At still higher pressure of !200 GPa, the B2 phase becomes not only the lowest enthalpy structure but also dynamically stable. These findings support the results of our static lattice calculations. Further, our calculated angle dispersive x-ray diffraction pattern of B1, B10, and B2 phases shows that most of the diffraction peaks of B10 phase except few weak peaks coincide with the peaks of either B1 or B2 phase; which may pose a difficulty in unambiguously identifying the high pressure phase until a sufficient amount of B1 phase is transformed to the new structure so that the weak peaks, if present, are also visible.

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