Microscopic origin of pressure-induced phase transitions in the iron pnictide superconductors A Fe2 As2: An ab initio molecular dynamics study

Yu Zhong Zhang, Hem C. Kandpal, Ingo Opahle, Harald Olaf Jeschke, Roser Valentí

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Using ab initio molecular dynamics we investigate the electronic and lattice structure of A Fe2 As2 (A=Ca,Sr,Ba) under pressure. We find that the structural phase transition (orthorhombic to tetragonal symmetry) is always accompanied by a magnetic phase transition in all the compounds while the nature of the transitions is different for the three systems. Our calculations explain the origin of the existence of a collapsed tetragonal phase in CaFe2 As2 and its absence in BaFe2 As2. We argue that changes in the Fermi-surface nesting features dominate the phase transitions under pressure rather than spin frustration or a Kondo scenario. The consequences for superconductivity are discussed.

Original languageEnglish
Article number094530
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume80
Issue number9
DOIs
Publication statusPublished - Sep 30 2009
Externally publishedYes

Fingerprint

Group 5A compounds
Superconducting materials
Molecular dynamics
Iron
Phase transitions
molecular dynamics
iron
Fermi surface
Superconductivity
frustration
Fermi surfaces
superconductivity
electronic structure
symmetry

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Microscopic origin of pressure-induced phase transitions in the iron pnictide superconductors A Fe2 As2 : An ab initio molecular dynamics study. / Zhang, Yu Zhong; Kandpal, Hem C.; Opahle, Ingo; Jeschke, Harald Olaf; Valentí, Roser.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 80, No. 9, 094530, 30.09.2009.

Research output: Contribution to journalArticle

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