Low-Temperature Dielectric Anisotropy Driven by an Antiferroelectric Mode in SrTiO3

Blai Casals, Andrea Schiaffino, Arianna Casiraghi, Sampo J. Hämäläinen, Diego López González, Sebastiaan van Dijken, Massimiliano Stengel, and Gervasi Herranz
Phys. Rev. Lett. 120, 217601 – Published 25 May 2018
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Abstract

Strontium titanate (SrTiO3) is the quintessential material for oxide electronics. One of its hallmark features is the transition, driven by antiferrodistortive (AFD) lattice modes, from a cubic to a ferroelastic low-temperature phase. Here we investigate the evolution of the ferroelastic twin walls upon application of an electric field. Remarkably, we find that the dielectric anisotropy of tetragonal SrTiO3, rather than the intrinsic domain wall polarity, is the main driving force for the motion of the twins. Based on a combined first-principles and Landau-theory analysis, we show that such anisotropy is dominated by a trilinear coupling between the polarization, the AFD lattice tilts, and a previously overlooked antiferroelectric (AFE) mode. We identify the latter AFE phonon with the so-called “R mode” at 440cm1, which was previously detected in IR experiments, but whose microscopic nature was unknown.

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  • Received 21 September 2017
  • Revised 9 January 2018

DOI:https://doi.org/10.1103/PhysRevLett.120.217601

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Blai Casals1, Andrea Schiaffino1, Arianna Casiraghi2, Sampo J. Hämäläinen2, Diego López González2, Sebastiaan van Dijken2, Massimiliano Stengel1,3, and Gervasi Herranz1

  • 1Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia, Spain
  • 2NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
  • 3ICREA–Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys, 23, 08010 Barcelona, Catalonia, Spain

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Issue

Vol. 120, Iss. 21 — 25 May 2018

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