2010/04/12 by Vadim Ksenofontov, V. Ksenofontov, G. Wortmann +10
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Density of states #Diffraction #Iron-based superconductors research #Materials science #Optics #Orthorhombic crystal system #Phase (matter) #Phonon #Physics #Rare-earth and actinide compounds #Superconductivity #Tetragonal crystal system #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.81.184510
arxiv created 2010/04/12 · openalex publication_date 2010/05/13 · arxiv updated 2015/05/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The temperature and pressure dependence of the partial density of phonon states (phonon-DOS) of iron atoms in superconducting Fe1.01Se was studied by 57Fe nuclear inelastic scattering. The high-energy resolution allows for a detailed observation of spectral properties. A sharpening of the optical phonon modes and shift of all spectral features toward higher energies by \ensuremath∼4% with decreasing temperature from 296 to 10 K was found. However, no detectable change at the tetragonal--orthorhombic phase transition around 100 K was observed. Application of a pressure of 6.7 GPa, connected with an increase in the superconducting temperature from 8 to 34 K, results in an increase in the optical phonon mode energies at 296 K by \ensuremath∼12%, and an even more pronounced increase for the lowest-lying transversal acoustic mode. Despite these strong pressure-induced modifications of the phonon-DOS we conclude that the pronounced increase in Tc in Fe1.01Se with pressure cannot be described in the framework of classical electron-phonon coupling. This result suggests the importance of spin fluctuations to the observed superconductivity.