Uniaxial Strain-Controlled Ground States in Manganite Films

Feng Jin; Mingqiang Gu; Chao Ma; Er-Jia Guo; Jin Zhu; Lili Qu; Zixun Zhang; Kexuan Zhang; Liqiang Xu; Binbin Chen; Feng Chen; Guanyin Gao; James M Rondinelli; Wenbin Wu

doi:10.1021/acs.nanolett.9b04506

Uniaxial Strain-Controlled Ground States in Manganite Films

Nano Lett. 2020 Feb 12;20(2):1131-1140. doi: 10.1021/acs.nanolett.9b04506. Epub 2020 Jan 30.

Authors

Feng Jin¹, Mingqiang Gu², Chao Ma³, Er-Jia Guo^{4

5}, Jin Zhu¹, Lili Qu¹, Zixun Zhang¹, Kexuan Zhang¹, Liqiang Xu¹, Binbin Chen¹, Feng Chen¹, Guanyin Gao¹, James M Rondinelli², Wenbin Wu^{1

6

7}

Affiliations

¹ Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China.
² Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States.
³ College of Materials Science and Engineering , Hunan University , Changsha 410082 , China.
⁴ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China.
⁵ Center of Materials Science and Optoelectronics Engineering , University of Chinese Academy of Sciences , Beijing 100049 , China.
⁶ Institutes of Physical Science and Information Technology , Anhui University , Hefei 230601 , China.
⁷ Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China.

PMID: 31978309
DOI: 10.1021/acs.nanolett.9b04506

Abstract

Strongly correlated perovskite oxides exhibit a plethera of intriguing phenomena and stimulate a great potential for multifunctional device applications. Utilizing tunable uniaxial strain, rather than biaxial or anisotropic strain, delivered from the crystallography of a single crystal substrate to modify the ground state of strongly correlated perovskite oxides has rarely been addressed for phase-space control. Here, we show that the physical properties of La_2/3Ca_1/3MnO₃ (LCMO) films are remarkably different depending on the crystallographic orientations of the orthorhombic NdGaO₃ (NGO) substrates. More importantly, the antiferromagnetic charge-ordered insulating (COI) phase induced in the (100) or (001)-oriented LCMO films can be dramatically promoted (or suppressed) by a uniaxial tensile (or compressive) bending stress along the in-plane [010] direction. By contrast, the COI phase is nearly unaffected along the other transverse in-plane directions. Results from scanning transmission electron microscopy reveal that the (100)- or (001)-oriented LCMO films are uniaxially tensile strained along the [010] direction, while the LCMO/NGO(010) and LCMO/NGO(110) films remaining as a bulklike ferromagnetic metallic state exhibit a different strain state. Density functional theory calculations further reveal that the cooperatively increased Jahn-Teller distortion and charge ordering may be indispensible for the inducing and promoting of the COI phase. These findings provide a path to understand the correlation between local and extended structural distortions imparted by coherent epitaxy and the electronic states for quantum phase engineering.

Keywords: density functional theory calculations; manganite thin films; phase separation; scanning transmission electron microscopy; uniaxial strain engineering.