Supporting Information
Tunable topological domain structures in high-density PbTiO3
nanodots array
Hongying Chen,1,4 Zhiyu Liu,4 Guo Tian,1,2,* Gui Wang,1 Yihang Guo,1 Zongwen Duan,1 Di Wu,4
Yu Deng,4 Guoyu Wang, 5,* Zhipeng Hou,1 Deyang Chen,1 Zhen Fan,1 Minghui Qin,1 Ji-Yan Dai,2
Jun-Ming Liu1,3 and Xingsen Gao1,*
1Guangdong
Provincial Key Laboratory of Quantum Engineering and Quantum Materials and
Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China
Normal University, Guangzhou 510006, China
2Department
of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China
3Laboratory
of Solid-State Microstructures and Innovation Center of Advanced Microstructures,
Nanjing University, Nanjing 210093, China
4National Laboratory of Solid-State Microstructures, Department of Materials Science and
Engineering, and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University,
Nanjing 210093, China
5College
of Materials Science and Engineering and Center of Quantum Materials and Devices,
Chongqing University, Chongqing 401331, P. R. China
*Author to whom correspondence should be addressed: guotian@m.scnu.edu.cn;
gywang2022@cqu.edu.cn; xingsengao@scnu.edu.cn
Series title:
S1: Domain structures of the PTO film
S2: Schematic flowchart illustrating the procedures of fabricating the PTO nanodots array on the
SRO/STO film.
S3: Domain structures of the PTO nanodots array acquired by aligning the cantilever at 0º, 45º and
90º to the [010] direction.
S4: Reciprocal space mapping of the PTO film and PTO nanodots array around the SrTiO3 (103)
diffraction.
S5: HAADF-STEM image and GPA εxx (in-plane) map of a part of a PTO nanodots.
S6: Retention testing of the domain structure.
Experimental Section:
Growth of PTO nanodots.
Here, the PTO thin films were deposited on SrRuO3 buffered (100)-oriented SrTiO3 (STO)
substrates via pulsed laser deposition (PLD) using a KrF excimer laser (wavelength λ = 248 nm).
The ordered arrays of nanodots were patterned by mask-assisted etching techniques, the details of
which can be found elsewhere. Briefly, a layer of polystyrene (PS) nanospheres were first laid on
top of a PTO film to form an ordered, tightly packed monolayer template. Then, the prepared sample
is subjected to a 20-minute plasma etching to reduce the size of the nanospheres, followed by an
Ar+ ion beam etching process. Finally, the PS template was lifted off with chloroformic solution to
obtain an array of ordered PTO nanodots.
Structure and Morphology Analysis.
The morphology of the thin films and the nanodots were characterized by atomic force
microscopy (AFM, Cypher, Asylum Research). The crystalline structures of samples were measured
by X-ray diffraction and reciprocal mapping (PANalytical X’Pert PRO). Aberration-corrected
HAADF-STEM imaging of the heterostructure cross-section was acquired by an FEI Titan3 G2 60-
300 microscope at 300 kV
PFM and CAFM Analysis.
The domain structures of the thin films and the nanodots were characterized by piezoresponse
force microscopy (PFM, Cypher, Asylum Research). The local current−voltage curves and the
current maps of the nanodots were tested by conductive atomic force microscopy (C-AFM, Cypher,
Asylum Research).
Fig. S1. (a) Topography image of PTO film measured by AFM. (b-e) Vertical and lateral PFM
amplitude and phase images. (f-i) Vertical and lateral PFM amplitude and phase images, pre-poled
by scanning bias voltages of −3V/+3V.
Fig. S2. (a) Schematic flowchart illustrating the procedures of fabricating the PTO nanodots array
on the SRO/STO film. (b) Topography image of the selected PTO nanodots array measured by AFM.
And the height across the nanodots along the blue lines in the topography image.
Fig. S3. (a) Vertical PFM phase and amplitude images. (b-d) Topography (b), lateral PFM
amplitude (c) and phase (d) images acquired by aligning the cantilever at 0º,45ºand 90ºto the [010]
direction, as shown in the inset.
Fig. S4. Reciprocal space mapping of the PbTiO3 film (a) and PTO nanodots array(b) around the
SrTiO3 (103) diffraction.
Fig. S5. (a) HAADF-STEM image of the PTO nanodots along the [010] direction. (b) The GPA
εxx (in-plane) map of panel (a).
Fig. S6. (a) Vertical and lateral PFM amplitude and phase images and schematic 3-dimensional
polarization distribution of the nanodots. (b-e), The vector PFM images of the same region
acquired after scanning the tip biased in sequence at -2.0 V (b) and 3.5 V (c) and both remain
stable for over 48 hours at room temperature.
