Ambipolar ferromagnetism by electrostatic doping of a manganite

L M Zheng; X Renshaw Wang; W M Lü; C J Li; T R Paudel; Z Q Liu; Z Huang; S W Zeng; Kun Han; Z H Chen; X P Qiu; M S Li; Shize Yang; B Yang; Matthew F Chisholm; L W Martin; S J Pennycook; E Y Tsymbal; J M D Coey; W W Cao

doi:10.1038/s41467-018-04233-5

Ambipolar ferromagnetism by electrostatic doping of a manganite

Nat Commun. 2018 May 15;9(1):1897. doi: 10.1038/s41467-018-04233-5.

Authors

L M Zheng¹, X Renshaw Wang², W M Lü³, C J Li⁴, T R Paudel⁵, Z Q Liu⁶, Z Huang⁷, S W Zeng⁷, Kun Han⁷, Z H Chen^{8

9

10}, X P Qiu¹¹, M S Li⁴, Shize Yang¹², B Yang¹, Matthew F Chisholm¹², L W Martin^{8

9}, S J Pennycook⁴, E Y Tsymbal⁵, J M D Coey^{13

14}, W W Cao^{1

15}

Affiliations

¹ Condensed Matter Science and Technology Institute, School of Science, Harbin Institute of Technology, Harbin, 150081, China.
² School of Physical and Mathematical Sciences & School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore. renshaw@ntu.edu.sg.
³ Condensed Matter Science and Technology Institute, School of Science, Harbin Institute of Technology, Harbin, 150081, China. weiminglv@hit.edu.cn.
⁴ Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore.
⁵ Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska, 68588, USA.
⁶ School of Materials Science and Engineering, Beihang University, Beijing, 100191, China.
⁷ NUSNNI-NanoCore, National University of Singapore, Singapore, 117411, Singapore.
⁸ Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA.
⁹ Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
¹⁰ School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen, Guangzhou, 518055, China.
¹¹ Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & Pohl Institute of Solid State Physics & School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China.
¹² Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
¹³ School of Physics, Trinity College, Dublin, 2, Ireland.
¹⁴ Faculty of Materials Science and Engineering, Beihang University, Beijing, 100191, China.
¹⁵ Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA.

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.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.