AFe2As2 (A = Ca, Sr, Ba, Eu) and SrFe_(2-x)TM_(x)As2 (TM = Mn, Co, Ni): crystal structure, charge doping, magnetism and superconductivity

Abstract

The electronic structure and physical properties of the pnictide compound families $RE$OFeAs ($RE$ = La, Ce, Pr, Nd, Sm), $A$Fe${}_2$As${}_2$ ($A$ = Ca, Sr, Ba, Eu), LiFeAs and FeSe are quite similar. Here, we focus on the members of the $A$Fe${}_2$As${}_2$ family whose sample composition, quality and single crystal growth are better controllable compared to the other systems. Using first principles band structure calculations we focus on understanding the relationship between the crystal structure, charge doping and magnetism in $A$Fe${}_2$As${}_2$ systems. We will elaborate on the tetragonal to orthorhombic structural distortion along with the associated magnetic order and anisotropy, influence of doping on the $A$ site as well as on the Fe site, and the changes in the electronic structure as a function of pressure. Experimentally, we investigate the substitution of Fe in SrFe${}_{2-x}T{M}_x$As${}_2$ by other 3$d$ transition metals, $TM$ = Mn, Co, Ni. In contrast to a partial substitution of Fe by Co or Ni (electron doping) a corresponding Mn partial substitution does not lead to the supression of the antiferromagnetic order or the appearance of superconductivity. Most calculated properties agree well with the measured properties, but several of them are sensitive to the As $z$ position. For a microscopic understanding of the electronic structure of this new family of superconductors this structural feature related to the Fe-As interplay is crucial, but its correct ab initio treatment still remains an open question.

27 pages, single column

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Cited by in corpus (19)

• Effects of the magnetic orderings on the dynamical conductivity: optical investigations of EuFe${}_2$As${}_2$ single crystals
• Superconductivity induced by ruthenium substitution in an iron arsenide: investigation of SrFe2-xRuxAs2 (0 <= x <= 2)
• Microscopic origin of pressure-induced phase transitions in iron-pnictide $AF{e}_{2}A{s}_2$ superconductors: an {ab initio} molecular-dynamics study
• Effects of cobalt doping and three-dimensionality in $BaF{e}_{2}A{s}_2$
• Electronic structure of BaCu${}_2$As${}_2$ and SrCu${}_2$As${}_2$: sp-band metals
• Superconductivity without Fe or Ni in the phosphides BaIr2P2 and BaRh2P2
• Itinerant Nature of Magnetism in Iron Pnictides: A first principles study
• Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
• Magnetic and lattice coupling in single-crystal SrFe${}_2$As${}_2$: A neutron scattering study
• Superconductivity and magnetism in platinum-substituted SrFe2As2 single crystals
• Origin of structural and magnetic transitions in BaFe${}_{2-x}$Ru${}_x$As${}_2$ materials
• Magnetism and superconductivity in the layered hexagonal transition metal pnictides
• Pressure-induced ferromagnetism due to an anisotropic electronic topological transition in Fe1.08Te
• Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Electronic origin of structural transition in 122 Fe based superconductors
• Study of the hyperfine fields in the BaFe${}_2$As${}_2$ family and its relation to the magnetic moment
• Superconductivity on the verge of electronic topological transition in Fe based superconductors
• Evolution of structure, magnetic and transport properties of Fe${}_{1-x}$Mn${}_x$Se
• Effect of Co doping and hydrostatic pressure on SrFe2As2