Flexoelectric control of a ferromagnetic metal

Electric fields have played a key role in discovering and controlling exotic electronic states of condensed matter. However, electric fields usually do not work in metals as free carriers tend to screen electrostatic fields. While a pseudo-electric field generated by inhomogeneous lattice strain, na...

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Bibliographic Details
Published in:arXiv.org 2022-03
Main Authors: Peng, Wei, Se Young Park, Chang Jae Roh, Mun, Junsik, Ju, Hwiin, Kim, Jinkwon, Ko, Eun Kyo, Liang, Zhengguo, Hahn, Sungsoo, Zhang, Jinfeng, Liang, Si, Yong Jin Jo, Kim, Tae Heon, Kim, Changyoung, Wang, Lingfei, Kim, Miyoung, Lee, Jong Seok, Noh, Tae Won, Lee, Daesu
Format: Article
Language:English
Subjects:
Displacement
Electric fields
Electron states
Electrostriction
Ferromagnetism
Lattice strain
Metal oxides
Online Access:Get full text
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Summary:Electric fields have played a key role in discovering and controlling exotic electronic states of condensed matter. However, electric fields usually do not work in metals as free carriers tend to screen electrostatic fields. While a pseudo-electric field generated by inhomogeneous lattice strain, namely a flexoelectric field, can in principle work in all classes of materials, it remains experimentally unexplored in metals. Here, using heteroepitaxy and atomic-scale imaging, we show that flexoelectric fields can polarize a metallic oxide SrRuO3 with unexpectedly large Ru off-center displacements. We also observe that the flexoelectrically induced polar state of SrRuO3 leads to sizable lattice expansion, similar to the electrostrictive expansion caused by ionic displacements in dielectrics under an external electric field. We further suggest that flexoelectrically driven Ru off-centering promotes strong coupling between lattice and electronic degrees of freedom, possibly enhancing the ferromagnetism of SrRuO3. Beyond conventional electric fields, flexoelectric fields may universally engender novel electronic states and their control via pure atomic displacements in a nondestructive and fast manner.
ISSN:2331-8422
DOI:10.48550/arxiv.2203.03199