Supercell studies of the Fermi surface changes in the electron-doped superconductor LaFeAsO$ {1-x}$F$ x$ - Condensed Matter > Materials ScienceReportar como inadecuado




Supercell studies of the Fermi surface changes in the electron-doped superconductor LaFeAsO$ {1-x}$F$ x$ - Condensed Matter > Materials Science - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We study the changes in the Fermi surface with electron doping in theLaFeAsO$ {1-x}$F$ x$ superconductors with density-functional supercellcalculations using the linearized augmented planewave LAPW method. Thesupercell calculations with explicit F substitution are compared with thoseobtained from the virtual crystal approximation VCA and from a simple rigidband shift. We find significant differences between the supercell results andthose obtained from the rigid-band shift with electron doping, although quiteremarkably the supercell results are in good agreement with the virtual crystalapproximation VCA where the nuclear charges of the O atoms are slightlyincreased to mimic the addition of the extra electrons. With electron doping,the two cylindrical hole pockets along $\Gamma-Z$ shrink in size, and the thirdhole pocket around $Z$ disappears for an electron doping concentration inexcess of about 7-8%, while the two elliptical electron cylinders along $M-A$expand in size. The spin-orbit coupling does not affect the Fermi surface muchexcept to somewhat reduce the size of the third hole pocket in the undopedcase. We find that with the addition of the electrons the antiferromagneticstate becomes energetically less stable as compared to the nonmagnetic state,indicating that the electron doping may provide an extra degree of stability tothe formation of the superconducting ground state.



Autor: P. Larson, S. Satpathy

Fuente: https://arxiv.org/







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