Observation of room-temperature polar skyrmions.

Autor: Das S; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA. sujitdas@berkeley.edu., Tang YL; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Hong Z; Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA., Gonçalves MAP; Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Esch/Alzette, Luxembourg., McCarter MR; Department of Physics, University of California, Berkeley, CA, USA., Klewe C; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Nguyen KX; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA., Gómez-Ortiz F; Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Santander, Spain., Shafer P; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Arenholz E; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Stoica VA; Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA., Hsu SL; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.; National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Wang B; Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA., Ophus C; National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Liu JF; Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Nelson CT; Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA., Saremi S; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA., Prasad B; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA., Mei AB; Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA., Schlom DG; Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA.; Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA., Íñiguez J; Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Esch/Alzette, Luxembourg.; Physics and Material Science Research Unit, University of Luxembourg, Belvaux, Luxembourg., García-Fernández P; Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Santander, Spain., Muller DA; Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.; School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA., Chen LQ; Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA., Junquera J; Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Santander, Spain., Martin LW; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Ramesh R; Department of Materials Science and Engineering, University of California, Berkeley, CA, USA. rramesh@berkeley.edu.; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. rramesh@berkeley.edu.; Department of Physics, University of California, Berkeley, CA, USA. rramesh@berkeley.edu.
Jazyk: angličtina
Zdroj: Nature [Nature] 2019 Apr; Vol. 568 (7752), pp. 368-372. Date of Electronic Publication: 2019 Apr 17.
DOI: 10.1038/s41586-019-1092-8
Abstrakt: 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 (PbTiO 3 ) n /(SrTiO 3 ) n suggests the presence of a complex, multi-dimensional system capable of interesting physical responses, such as chirality, negative capacitance and large piezo-electric responses 1-3 . 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.
Databáze: MEDLINE