Strain effects on electronic structure and superconductivity in the iron telluride

Abstract

The influence of tensile strain in the ab-plane on crystal and electronic structure of FeTe has been studied ab initio. In superconducting FeSe the Fermi surface nesting with a vector q ∼ (0.5, 0.5) × (2π/a) is believed to be crucial for rising superconductivity mediated by spin-fluctuations. The results presented here indicate that tensile-strained FeTe also exhibits such conditions. Furthermore, the Fermi surface changes, related to the increase of the lattice parameter a of this telluride, are opposite to analogous effects reported for FeSe. Since a recently reported transition from the double-stripe to the single-stripe magnetic order in FeTe under tensile strain in the ab-plane is associated with an occurrence of superconductivity in corresponding thin films, these findings allow for drawing a consistent picture of superconductivity in FeSe 1−x Te x systems, in general.

Electronic structure of ruthenium-doped iron chalcogenides

“…2. The overall shapes of the total DOSs for FeSe and FeTe are similar to those reported earlier, [25][26][27]29,30,33,34 being dominated by the Fe 3d FIG. 1.…”

“…16 However, the same analysis of the FS nesting for RuTe leads to opposite conclusions; SC can be raised in the Ru x Fe 1Àx Te compounds similar to the results reported for tensile-strained FeTe. 33 Namely, the intensity of f nest for the ideal vector Q is diminished, though the overall shape of f nest resembles that of FeSe. The predicted structural parameters and electronic properties of RuSe and RuTe suggest that the Ru-doped iron chalcogenides are possible candidates for new superconductors.…”

“…15 The electronic structure of FeSe-based superconductors has been extensively investigated in both experimental [20][21][22][23][24] and theoretical studies. [25][26][27][28][29][30][31][32][33][34] It is believed that the multi-gap SC in 11-type compounds originates from the interband interactions between the holelike b and electronlike d Fermi surface (FS) sheets. In particular, SC can be mediated by antiferromagnetic (AFM) spin fluctuations, 35,36 which are driven by the imperfect nesting with the q % (0.5, 0.5) Â (2p/a) vector, spanning the above FS sheets in the iron chalcogenides.…”

“…In particular, SC can be mediated by antiferromagnetic (AFM) spin fluctuations, 35,36 which are driven by the imperfect nesting with the q % (0.5, 0.5) Â (2p/a) vector, spanning the above FS sheets in the iron chalcogenides. 25,27,[29][30][31]33 Furthermore, such fluctuations are related to the single-stripe AFM order, while compounds with the double-stripe AFM order do not exhibit SC. 37 The magnetic ordering in iron chalcogenides is closely connected with the chalcogen atom position in the unit cell.…”

Magnetism and superconductivity of S-substituted FeTe

“…The results indicate that the magnetic ordering and superconductivity in iron chalcogenides is closely connected with the crystal structure. Interestingly, the tensile strain applied to FeTe enhances the (π, π) nesting [38], analogously to the case of superconducting Fe(Te,Se) systems [39,40].…”