Unfolding of electronic structure through induced representations of space groups: Application to Fe-based superconductors

Milan Tomić, Harald Olaf Jeschke, Roser Valentí

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

We revisit the problem that relevant parts of band structures for a given cell choice can reflect exact or approximate higher symmetries of subsystems in the cell and can therefore be significantly simplified by an unfolding procedure that recovers the higher symmetry. We show that band-structure unfolding can be understood as projection onto induced irreducible representations of a group obtained by extending the original group of translations with a number of additional symmetry operations. The resulting framework allows us to define a generalized unfolding procedure that includes the point group operations and can be applied to any quantity in the reciprocal space. The unfolding of the Brillouin zone follows naturally from the properties of the induced irreducible representations. In this context, we also introduce a procedure to derive tight-binding models of reduced dimensionality by making use of point group symmetries. Further, we show that careful consideration of unfolding has important consequences on the interpretation of angle-resolved photoemission experiments. Finally, we apply the unfolding procedure to various representative examples of Fe-based superconductor compounds and show that the one-iron picture arises as an irreducible representation of the glide-reflection group, and we comment on the consequences for the interpretation of one-iron versus two-iron Brillouin zone representations.

Original languageEnglish
Article number195121
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume90
Issue number19
DOIs
Publication statusPublished - Nov 12 2014
Externally publishedYes

Fingerprint

Electronic structure
Point groups
Iron
Crystal symmetry
electronic structure
Band structure
symmetry
Brillouin zones
iron
Photoemission
cells
photoelectric emission
projection
Iron-based Superconductors
Experiments

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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