Ab Initio, Mean Field and Series Expansions Calculations Study of Structural, Electronic and Magnetic Properties of MnAs

Masrour, R.; Hlil, E.K.; Hamedoun, M.; Benyoussef, A.; Mounkachi, O.; Moussaoui, H. El

doi:10.1007/s10948-014-2638-5

Cited by 3 publications

(1 citation statement)

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“…Concerning the structural stabilities, the competition between the hexagonal NiAs structure and the orthorhombic MnP structure was explained by different d-electron counts for simple 3d transition-metal phosphides [3], where counts below three favour the NiAs structure, while for higher counts the lower symmetry MnP phase is stabilized due to an increased metal-metal interaction. In the present invest igation, the d-electron count is fixed and only the non-metal atoms change moving down the pnictogen group from P to Bi increasing the volume and favoring the NiAs structure beyond P. Quite a few DFT and DFT+U calculations exist for MnP [4][5][6][7][8][9][10], MnAs [2,4,5,[11][12][13][14][15][16][17][18], MnSb [4,5,11,13,[19][20][21][22][23][24] and MnBi [11,13,[25][26][27][28][29][30] focussing mostly on magnetic properties.…”

Section: Introductionmentioning

confidence: 91%

Density functional theory study of structural and thermodynamical stabilities of ferromagnetic MnX (X = P, As, Sb, Bi) compounds

Podloucky

Redinger

2018

J. Phys.: Condens. Matter

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Density functional theory (DFT) calculations for deriving enthalpies of formation ∆H for ferromagnetic MnX (X = P, As, Sb, Bi) compounds were made for the two competing structures, hexagonal B8 1 and orthorhombic B3 1 . Standard calculations were performed by using pseudopotentials with the generalized-gradient-approximation (PBE) as exchangecorrelation functional. Enhanced exchange-correlation interactions were included by making use of a so-called DFT+U approach which requires U eff = (U − J) as a parameter. Application of PBE potentials for all compounds and elementary phases (all-PBE) resulted in negative values of ∆H for MnP and MnAs in both structures whereby the result for MnP B3 1 agrees very well with experiment. For MnSb and MnBi the all-PBE calculation gives a positive nonbonding ∆H disagreeing with experiment. To overcome this discrepancy for MnSb and MnBi a DFT+U ansatz was employed for all compounds and elemental Mn. The values for U eff ranging between 0.7 for MnBi and 1.4 eV for MnAs were determined by fitting the DFT results to measured data of ∆H. As a reference for pure Mn the γ-Mn phase was taken with U eff = 1.3 eV by which choice the experimental volume is fitted. Atomic volumes and ionicities were derived applying Bader's concept resulting in ionicities of Mn less than +0.7.

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