Colossal flexoresistance in dielectrics

Sung Min Park, Bo Wang, Tula Paudel, Se Young Park, Saikat Das, Jeong Rae Kim, Eun Kyo Ko, Han Gyeol Lee, Nahee Park, Lingling Tao, Dongseok Suh, Evgeny Y. Tsymbal, Long Qing Chen, Tae Won Noh, Daesu Lee

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Dielectrics have long been considered as unsuitable for pure electrical switches; under weak electric fields, they show extremely low conductivity, whereas under strong fields, they suffer from irreversible damage. Here, we show that flexoelectricity enables damage-free exposure of dielectrics to strong electric fields, leading to reversible switching between electrical states—insulating and conducting. Applying strain gradients with an atomic force microscope tip polarizes an ultrathin film of an archetypal dielectric SrTiO3 via flexoelectricity, which in turn generates non-destructive, strong electrostatic fields. When the applied strain gradient exceeds a certain value, SrTiO3 suddenly becomes highly conductive, yielding at least around a 108-fold decrease in room-temperature resistivity. We explain this phenomenon, which we call the colossal flexoresistance, based on the abrupt increase in the tunneling conductance of ultrathin SrTiO3 under strain gradients. Our work extends the scope of electrical control in solids, and inspires further exploration of dielectric responses to strong electromechanical fields.

Original languageEnglish
Article number2586
JournalNature Communications
Volume11
Issue number1
DOIs
StatePublished - 1 Dec 2020

Bibliographical note

Funding Information:
This work was supported by the Research Center Program of the IBS (Institute for Basic Science) in Korea (grant no. IBS-R009-D1) and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2018R1A5A6075964 and No. 2019R1C1C1002558). D.L. acknowledges the support by Samsung Electronics Co., Ltd. B.W. acknowledges the support by the NSF-MRSEC grant number DMR-1420620. The effort of L.-Q.C. is supported by National Science Foundation (NSF) through Grant No. DMR-1744213. The research at the University of Nebraska−Lincoln is supported by the National Science Foundation through the Nebraska Materials Research Science and Engineering Center (MRSEC), Grant No. DMR-1420645.

Publisher Copyright:
© 2020, The Author(s).

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