Ab initio investigation of the anomalous phonon softening in FeSi

作者:Stern Robin; Madsen Georg K H*
来源:Physical Review B, 2016, 94(14): 144304.
DOI:10.1103/PhysRevB.94.144304

摘要

The anomalous softening of the acoustic phonon peak in FeSi has recently received considerable experimental attention. In our work, we investigate the effect of thermal disorder on the lattice dynamics and the filling of the narrow band gap of FeSi using density functional theory. We show, by comparing the phonon density of states from temperature-independent and temperature-dependent force constants, that thermal structural disorder together with thermal expansion explains the anomalously strong renormalization of the acoustic phonons. Furthermore, we find an intricate interplay between thermal disorder and volume in gap closure.

  • 出版日期2016-10-24