Milan Tomic, Roser Valenti, Harald O. Jeschke
Starting from the orthorhombic magnetically ordered phase, we investigate the effects of uniaxial tensile and compressive strains along a, b, and the diagonal a+b directions in BaFe2As2 and CaFe2As2 in the framework of ab initio density functional theory (DFT) calculations. While --contrary to the application of hydrostatic or c-axis uniaxial pressure-- both systems remain in the orthorhombic phase with a strain-dependent nonzero magnetic moment, we observe an inversion of magnetism at a critical strain happening when the a and b axes approach the tetragonal condition. Moreover, this is followed by a jump in orthorhombicity as well as a selective change of orbital occupancy. We discuss our results in view of recent reports of modified magnetic and structural transitions in BaFe2As2 under externally applied uniaxial strain.
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http://arxiv.org/abs/1210.5504
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