36 research outputs found
Strain effects on electronic structure of the iron selenide superconductor
The influence of various strains on crystal and electronic structures of
superconducting FeSe has been studied ab initio. We consider changes in the
Fermi surface nesting with a vector Q=(0.5,0.5)*(2\pi /a) as crucial for rising
superconductivity (SC) mediated by spin-fluctuations (SF). Our results indicate
that the c-axis strained FeSe exhibits the most imperfect nesting, which
enhances SF and, hence, also SC. In turn, the ab-plane compressive strain
slightly weakens this} nesting while the tensile strain destroys it completely.
These findings are consistent with reported earlier experimental dependencies
of superconducting transition temperatures on strain in FeSe thin films
The Pressure Effects on Electronic Structure of Iron Chalcogenide Superconductors FeSeTe
We study the electronic structure of iron-based superconductors
FeSeTe within the density functional theory. We pay particular
attention to the pressure effects on the Fermi surface (FS) topology, which
seem to be correlated with a critical superconducting temperature TC of iron
chalcogenides and pnictides. A reduction of the FS nesting between hole and
electron cylinders with increasing pressure is observed, which can lead to
higher values of TC . The tellurium substitution into selenium sites yields FS
changes similar to the pressure effect.Comment: 4 pages, 6 figures, 1 tabl