Pressure-induced phase transition and stability of EuO and EuS with NaCl structure

Gour, Atul; Singh, Sadhna; Singh, R. K.; Singh, Madhu

doi:10.1007/s12043-008-0151-8

Cited by 7 publications

(13 citation statements)

References 8 publications

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“…[16] Using the FP-LAPW scheme in the frame of the GGA. [7] , 36 [9] , 47 [4] 8.9 7.7 [9] 6.5 [3] EuS B1 → B2 22 20 [7] , 21 [13] , 27 [15] , 48.6 [16] , 20 [11] 22 [3] 8.7 14.5 [13] , 11.2 [15] , 6.6 [16] , 12 [11] 12.5 [3] EuSe B1 → B2 18 14 [7] , 9.5 [12] , 24 [15] , 8.9 [16] , 15 [11] 15 [3] 8.4 10.5 [15] , 6.1 [16] , 9.5 [11] 12.8 [3] EuTe B1 → B2 13.5 12 [7] , 9.9 [14] , 17.4 [16] , 10.5 [10] 11 [3] 7.9 8.23 [14] , 7.7 [16] , 8.8 [10] 11.6…”

Section: 661mentioning

confidence: 99%

Structural Stabilities and Elastic Constants of EuX (X = O, S, Se, and Te) Compounds at High Pressure

et al. 2013

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The structural stabilities, elastic properties and charge transfers of EuX (X = O, S, Se, Te) compounds as a function of pressure are investigated extensively using rst-principles calculations. The ground-state parameters, such as lattice constants, bulk modulus are predicted and compared with the available data, our results are satisfactory. The calculated phase transition pressures from the NaCl-type (B1) structure to the CsCl-type (B2) structure for EuX (X = O, S, Se, Te) also accord with the experiments. Particularly, the elastic constants of EuX (X = O, S, Se, Te) under zero pressure and high pressure are simulated appropriately for the rst time via density functional theory. The softening behaviors of the elastic shear modulus C44 under pressure for the B1 phase of EuX (X = O, S, Se, Te) are captured, which should be responsible for the pressure-induced structural phase transition in the EuX system. It is also suggested that the softening behavior might be induced partly by the p → d and f → d electron transfers of Eu atom under pressure. In addition, the aggregate elastic modulus (B, G, E), Poisson's ratio (σ), Debye temperature ΘD are also successfully obtained for both B1 and B2 phases of EuX.

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Section: 661mentioning

confidence: 99%

Structural Stabilities and Elastic Constants of EuX (X = O, S, Se, and Te) Compounds at High Pressure

et al. 2013

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“…At pressure less than 1.8 GPa SmS shows considerable volume collapse and change of colour but retains the same cubic structure [14]. Earlier, we had studied the high pressure phase transition phenomenon, elastic and various thermo-physical properties of SmTe and EuO successfully [15]. For SmS, at zero pressure, the Sm ions are in a divalent insulating state, the so-called black phase [16].…”

Section: Introductionmentioning

confidence: 99%

High Pressure Phase Transition and Allied Behavior οf Samarium Compounds

Singh

Gour²,

Singh

2013

Acta Phys. Pol. A

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A theoretical study of the phase transition of samarium monochalcogenides using three-body interaction potential model is carried out at high pressure. The three-body interaction potential includes long range Coulombic, three-body interaction forces and short range overlap repulsive forces operative up to next nearest neighbor ions. We have investigated phase transition pressures, volume collapses, elastic behavior, stability criteria and various thermo physical properties at various high pressure. The results found are well suited with available experimental data. In this paper third order elastic constants are also reported for the rst time which helps in understanding the nature of interionic forces in ionic solids which paved the experimentalist to work in specic direction.

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“…The pressure-volume behavior of EuX (X=O, S, Se, or Te) is somewhat different from that of the other members of the REC family. Several high-pressure studies have been performed on these compounds, and it ws observed that they undergo a first-order transition from a sixfoldcoordinated NaCl (B1) structure with space group Fm3m to an eightfold-coordinated CsCl (B2) structure with space group Pm3m [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Compounds where the Eu ion is in a divalent state (Eu 2+ ) are technologically important semiconducting materials, while compounds where the Eu ion belongs to the trivalent state (Eu 3+ ) due to the promotion of the f electron are metallic.…”

Section: Introductionmentioning

confidence: 99%

“…A study of the structural and elastic properties of these compounds had been reported in the literature [8][9][10][11][12][13][14][15][16][17][18]. The Debye temperatures of Eu compounds have been reported by Shapira et al [11], Benbattouche et al [13], and Subhadra et al [14].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Gour et al [17,18], Varshney et al [23], and Srivastava et al [24] computed a few crystal properties of Eu and some other RECs, but many of these-especially the elastic properties, Cauchy's discrepancy, and the pressure variation-are not explained very well due to the exclusion of covalency and CTI from the expressions for the elastic moduli. These interactions are responsible for the Coulomb screening due to the delocalized f electrons in the rare-earth ion.…”

Section: Introductionmentioning

confidence: 99%

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High-pressure phase transition and thermoelastic properties of europium chalcogenides

Gupta

Singh

2011

J Mol Model

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The pressure-induced crystal properties of Eu chalcogenides were investigated using two different models: a modified charge-transfer potential model consisting of Coulomb screening due to the delocalization of the f electron of the rare earth atom, and modified by covalency and zero-point energy effects along with attractive and repulsive interactions; and a charge-transfer model that excluded the covalency and zero-point energy effects in the previous model. Both models were used to visualize the effect of covalency on the mechanism of interaction of the constituent atoms. Eu chalcogenides transform from the Fm3m to the Pm3m phase under the influence of sufficient pressure (P(T) = 39.52, 21.01, 14.31, and 10.58 GPa), and their equations of state indicated decreases in volume during this phase transition of 6.38, 12.32, 12.76, and 11.15%, respectively, for EuO, EuS, EuSe, and EuTe. The results obtained from the models were in good agreement with corresponding experimental data. The elastic constants and Debye temperatures were also computed at normal and high pressures. Both of the models were found to be capable of successfully explaining these properties.

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Pressure-induced phase transition and stability of EuO and EuS with NaCl structure

Cited by 7 publications

References 8 publications

Structural Stabilities and Elastic Constants of EuX (X = O, S, Se, and Te) Compounds at High Pressure

Structural Stabilities and Elastic Constants of EuX (X = O, S, Se, and Te) Compounds at High Pressure

High Pressure Phase Transition and Allied Behavior οf Samarium Compounds

High-pressure phase transition and thermoelastic properties of europium chalcogenides

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