Publication Type:Journal Article
Source:Nature, Nature Publishing Group, Volume 568, Number 7752, p.368-372 (2019)
Keywords:chirality, circular dichroism, electric activity, electric capacitance, electric field, electromagnetism, Letter, Magnetism, Polarization, priority journal, room temperature, scanning transmission electron microscopy, titanium, transmission electron microscopy, X ray diffraction
Complex topological configurations are fertile ground for exploring emergent phenomena and exotic phases in condensed-matter physics. For example, the recent discovery of polarization vortices and their associated complex-phase coexistence and response under applied electric fields in superlattices of (PbTiO3)n/(SrTiO3)n suggests the presence of a complex, multi-dimensional system capable of interesting physical responses, such as chirality, negative capacitance and large piezo-electric responses1–3. Here, by varying epitaxial constraints, we discover room-temperature polar-skyrmion bubbles in a lead titanate layer confined by strontium titanate layers, which are imaged by atomic-resolution scanning transmission electron microscopy. Phase-field modelling and second-principles calculations reveal that the polar-skyrmion bubbles have a skyrmion number of +1, and resonant soft-X-ray diffraction experiments show circular dichroism, confirming chirality. Such nanometre-scale polar-skyrmion bubbles are the electric analogues of magnetic skyrmions, and could contribute to the advancement of ferroelectrics towards functionalities incorporating emergent chirality and electrically controllable negative capacitance. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
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