Ambipolar Ferromagnetism by Electrostatic Doping of a Manganite

Authors

L. M. Zheng, Harbin Institute of Technology, Harbin, China
X. Renshaw Wang, Nanyang Technological University, Singapore
W. M. Lü, Harbin Institute of Technology, Harbin, China
C. J. Li, National University of Singapore
Tula R. Paudel, University of Nebraska-LincolnFollow
Z. Q. Liu, Beihang University
Z. Huang, National University of Singapore
S. W. Zeng, National University of Singapore
Kun Han, National University of Singapore
Z. H. Chen, University of California, Berkeley
X. P. Qiu, Tongji University, Shanghai
M. S. Li, Harbin Institute of Technology, Harbin, China
Shize Yang, Oak Ridge National Laboratory
B. Yang, Harbin Institute of Technology, Harbin, China
Matthew F. Chisholm, Oak Ridge National Laboratory
L. W. Martin, University of California, BerkeleyFollow
S. J. Pennycook, National University of Singapore
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
J. M. D. Coey, Trinity College Dublin, Ireland
W. W. Cao, Pennsylvania State University

ORCID IDs

Tsymbal http://orcid.org/0000-0002-6728-5558

Paudel https://orcid.org/0000-0002-9952-9435

Document Type

Article

Date of this Version

5-15-2018

Citation

Nature Communications (2018) 9: 1897

doi: 10.1038/s41467-018-04233-5

Comments

Open access. License: Creative Commons Attribution 4.0 International (CC BY 4.0)

Abstract

Complex-oxide materials exhibit physical properties that involve the interplay of charge and spin degrees of freedom. However, an ambipolar oxide that is able to exhibit both electron-doped and hole-doped ferromagnetism in the same material has proved elusive. Here we report ambipolar ferromagnetism in LaMnO₃, with electron–hole asymmetry of the ferromagnetic order. Starting from an undoped atomically thin LaMnO₃ film, we electrostatically dope the material with electrons or holes according to the polarity of a voltage applied across an ionic liquid gate. Magnetotransport characterization reveals that an increase of either electron-doping or hole-doping induced ferromagnetic order in this antiferromagnetic compound, and leads to an insulator-to-metal transition with colossal magnetoresistance showing electron–hole asymmetry. These findings are supported by density functional theory calculations, showing that strengthening of the inter-plane ferromagnetic exchange interaction is the origin of the ambipolar ferromagnetism. The result raises the prospect of exploiting ambipolar magnetic functionality in strongly correlated electron systems.