Metastable ferroelectricity in optically strained \(SrTiO_3\)

Fluctuating orders in solids are generally considered high-temperature precursors of broken symmetry phases. However, in some cases these fluctuations persist to zero temperature and prevent the emergence of long-range order, as for example observed in quantum spin and dipolar liquids. \(SrTiO_3\) i...

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Bibliographic Details
Published in:arXiv.org 2018-12
Main Authors: Tobia Nova, Disa, Ankit, Fechner, Michael, Cavalleri, Andrea
Format: Article
Language:English
Subjects:
Broken symmetry
Domains
Ferroelectric materials
Ferroelectricity
High temperature
Lattice vibration
Long range order
Metastable phases
Nonlinearity
Optical pulses
Phase transitions
Spatial distribution
Variations
Online Access:Get full text
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Summary:Fluctuating orders in solids are generally considered high-temperature precursors of broken symmetry phases. However, in some cases these fluctuations persist to zero temperature and prevent the emergence of long-range order, as for example observed in quantum spin and dipolar liquids. \(SrTiO_3\) is a quantum paraelectric in which dipolar fluctuations grow when the material is cooled, although a long-range ferroelectric order never sets in. We show that the nonlinear excitation of lattice vibrations with mid-infrared optical pulses can induce polar order in \(SrTiO_3\) up to temperatures in excess of 290 K. This metastable phase, which persists for hours after the optical pump is interrupted, is evidenced by the appearance of a large second-order optical nonlinearity that is absent in equilibrium. Hardening of a low-frequency mode indicates that the polar order may be associated with a photo-induced ferroelectric phase transition. The spatial distribution of the optically induced polar domains suggests that a new type of photo-flexoelectric coupling triggers this effect.
ISSN:2331-8422
DOI:10.48550/arxiv.1812.10560