Phase and polarization modulation in two-dimensional In2Se3 via in situ transmission electron microscopy

Xiaodong Zheng; Wei Han; Ke Yang; Lok Wing Wong; Chi Shing Tsang; Ka Hei Lai; Fangyuan Zheng; Tiefeng Yang; Shu Ping Lau; Thuc Hue Ly; Ming Yang; Jiong Zhao

doi:10.1126/sciadv.abo0773

Phase and polarization modulation in two-dimensional In₂Se₃ via in situ transmission electron microscopy

Sci Adv. 2022 Oct 21;8(42):eabo0773. doi: 10.1126/sciadv.abo0773. Epub 2022 Oct 21.

Authors

Xiaodong Zheng^{1

2}, Wei Han^{1

2}, Ke Yang^{1

3}, Lok Wing Wong^{1

2}, Chi Shing Tsang¹, Ka Hei Lai¹, Fangyuan Zheng^{1

2}, Tiefeng Yang^{4

5}, Shu Ping Lau¹, Thuc Hue Ly^{4

5}, Ming Yang¹, Jiong Zhao^{1

2}

Affiliations

¹ Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
² The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
³ Department of Computing, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
⁴ Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong, China.
⁵ City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.

Abstract

Phase transitions in two-dimensional (2D) materials promise reversible modulation of material physical and chemical properties in a wide range of applications. 2D van der Waals layered In₂Se₃ with bistable out-of-plane ferroelectric (FE) α phase and antiferroelectric (AFE) β' phase is particularly attractive for its electronic applications. However, reversible phase transition in 2D In₂Se₃ remains challenging. Here, we introduce two factors, dimension (thickness) and strain, which can effectively modulate the phases of 2D In₂Se₃. We achieve reversible AFE and out-of-plane FE phase transition in 2D In₂Se₃ by delicate strain control inside a transmission electron microscope. In addition, the polarizations in 2D FE In₂Se₃ can also be manipulated in situ at the nanometer-sized contacts, rendering remarkable memristive behavior. Our in situ transmission electron microscopy (TEM) work paves a previously unidentified way for manipulating the correlated FE phases and highlights the great potentials of 2D ferroelectrics for nanoelectromechanical and memory device applications.