An Inelastic X-Ray investigation of the Ferroelectric Transition in SnTe

Abstract

We report that the lowest energy transverse-optic phonon in metallic SnTe softens to near zero energy at the structural transition at $T_C=75\text{ K}$ and importantly show that the energy of this mode below $T_C$ increases as the temperature decreases. Since the mode is a polar displacement this proves unambiguously that SnTe undergoes a ferroelectric displacement below $T_C$. Concentration gradients and imperfect stoichiometry in large crystals may explain why this was not seen in previous inelastic neutron scattering studies. Despite SnTe being metallic we find that the ferroelectric transition is similar to that in ferroelectric insulators, unmodified by the presence of conduction electrons: we find that (i) the damping of the polar mode is dominated by coupling to acoustic phonons rather than electron-phonon coupling (ii) the transition is almost an ideal continuous transition (iii) comparison with density functional calculations identifies the importance of dipolar-dipolar screening for understanding this behaviour.

5 pages main text with 4 figures. 5 pages of supplementary material with 7 figures

References in corpus (4)

• Giant Anharmonic Phonon Scattering in PbTe
• A ferroelectric-like structural transition in a metal
• Entropy driven stabilization of energetically unstable crystal structures explained from first principles theory
• SU(3) Quantum Hall Ferromagnetism in SnTe

Cited by in corpus (16)

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• Strong anharmonicity and high thermoelectric efficiency in high temperature SnS from first-principles
• From atomic layer to the bulk: low-temperature atomistic structure, ferroelectric and electronic properties of SnTe films
• Anomalous transverse optic phonons in SnTe and PbTe -- revisited
• Towards temperature-induced topological phase transition in SnTe: A first principles study
• Changes of Fermi Surface Topology due to the Rhombohedral Distortion in SnTe
• Unusual phonon density of states and response to the superconducting transition in the In-doped topological crystalline insulator Pb${}_{0.5}$Sn${}_{0.5}$Te
• Imitation of spin density wave order in Cu${}_3$Nb${}_2$O${}_8$
• Electron-phonon coupling and superconductivity in the doped topological-crystalline insulator (Pb${}_{0.5}$Sn${}_{0.5}$)${}_{1-x}$In${}_x$Te
• Thermal topological phase transition in SnTe from \emph{ab-initio} calculations
• Broadband critical dynamics in disordered lead-based perovskites
• Metallicity-driven polar transitions in topological epilayers
• Berry curvature generation detected by Nernst responses in ferroelectric Weyl semimetal
• Anomalies in the temperature evolution of the Dirac states in a topological crystalline insulator SnTe