Flexoelectric control of a ferromagnetic metal

Abstract

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.

33 pages, 13 figures

References in corpus (3)

• Enhanced flexoelectricity at reduced dimensions revealed by mechanically tunable quantum tunnelling
• Electronic correlations, magnetism and Hund's rule coupling in the ruthenium perovskites SrRuO${}_3$ and CaRuO${}_3$
• A compact and stable incidence-plane-rotating second harmonics detector

Cited by in corpus (4)

• Dimensionality Engineering of Magnetic Anisotropy from Anomalous Hall Effect in Synthetic SrRuO3 Crystals
• Superconducting Diode Effect in Gradiently Strained Nb0.5Ti0.5N Films
• Propagation of elastic waves in a flexomagnetic solid
• Charge disproportionation as a possible mechanism towards polar antiferromagnetic metal in molecular orbital crystal