Institute of Plastics and Circular Economy Research Publications
Converse Flexoelectricity in van der Waals (vdW) Three-Dimensional Topological Insulator Nanoflakes

Converse Flexoelectricity in van der Waals (vdW) Three-Dimensional Topological Insulator Nanoflakes

Categories Zeitschriften/Aufsätze (reviewed)
Year 2024
Authors Q. Liu, S. S. Nanthakumar, B. Li, T. Cheng, F. Bittner, C. Ma, F. Ding, L. Zheng, B. Roth, X. Zhuang
Published in The Journal of Physical Chemistry C 2024, 128, 38, 16265–16273
Description

Low-dimensional van der Waals (vdW) three-dimensional (3D) topological insulators (TIs) have been overlooked, regarding their electromechanical properties. In this study, we experimentally investigate the electromechanical coupling of low-dimensional 3D TIs with a centrosymmetric crystal structure, where a binary compound, bismuth selenide (Bi2Se3), is taken as an example. Piezoresponse force microscopy (PFM) results of Bi2Se3 nanoflakes show that the material exhibits both out-of-plane and in-plane electromechanical responses. With careful analyses, the electromechanical responses are verified to arise from the converse flexoelectricity. The Bi2Se3 nanoflakes have a decreasing effective out-of-plane piezoelectric coefficient d33eff with the thickness increasing, with the d33eff value of ∼0.65 pm V–1 for the 37 nm-thick sample. The measured effective out-of-plane piezoelectric coefficient is mainly contributed by the flexoelectric coefficient, μ39, which is estimated to be approximately 0.13 nC m–1. The results can help to understand the flexoelectricity of low-dimensional vdW TIs with centrosymmetric crystal structures, which is crucial for the design of nanoelectromechanical devices and spintronics built by vdW TIs.

DOI 10.1021/acs.jpcc.4c05690