AUTHOR=Linker Thomas , Fukushima Shogo , Kalia Rajiv K. , Krishnamoorthy Aravind , Nakano Aiichiro , Nomura Ken-ichi , Shimamura Kohei , Shimojo Fuyuki , Vashishta Priya 

TITLE=Towards computational polar-topotronics: Multiscale neural-network quantum molecular dynamics simulations of polar vortex states in SrTiO3/PbTiO3 nanowires

JOURNAL=Frontiers in Nanotechnology

VOLUME=4

YEAR=2022

URL=https://www.frontiersin.org/journals/nanotechnology/articles/10.3389/fnano.2022.884149

DOI=10.3389/fnano.2022.884149

ISSN=2673-3013

ABSTRACT=<p>Recent discoveries of polar topological structures (<italic>e.g</italic>., skyrmions and merons) in ferroelectric/paraelectric heterostructures have opened a new field of polar topotronics. However, how complex interplay of photoexcitation, electric field and mechanical strain controls these topological structures remains elusive. To address this challenge, we have developed a computational approach at the nexus of machine learning and first-principles simulations. Our multiscale neural-network quantum molecular dynamics molecular mechanics approach achieves orders-of-magnitude faster computation, while maintaining quantum-mechanical accuracy for atoms within the region of interest. This approach has enabled us to investigate the dynamics of vortex states formed in PbTiO<sub>3</sub> nanowires embedded in SrTiO<sub>3</sub>. We find topological switching of these vortex states to topologically trivial, uniformly polarized states using electric field and trivial domain-wall states using shear strain. These results, along with our earlier results on optical control of polar topology, suggest an exciting new avenue toward opto-electro-mechanical control of ultrafast, ultralow-power polar topotronic devices.</p>