2008/12/23 by Victor Barzykin, L. P. Gor’kov, Lev P. Gor'kov · 1 citation
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Rare-earth and actinide compounds #cond-mat.mtrl-sci #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.79.134510
published as Phys. Rev. B 79, 134510 (2009) · Corrected typo
arxiv created 2008/12/23 · openalex publication_date 2009/04/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss the role of striction in the intertwined magnetic and structural phase transitions in the underdoped iron pnictides. The magnetoelastic coupling to acoustic modes is then derived and estimated in framework of the multiband spectrum for itinerant electrons with nesting features. We argue that the first-order character of the magnetoelastic phase transition originates from the lattice instabilities near the onset of spin-density wave order introducing, thus, a shear acoustic mode as another order parameter. Taking nonharmonic terms in the lattice energy into account may explain the splitting of the structural and magnetic transitions in some oxypnictides. Fluctuations of the magnetic order parameter show up in the precursory temperature dependence of the elastic moduli.