Peculiar Piezoelectric Properties of Soft Two-Dimensional Materials

• Published in: Journal of physical chemistry. C Vol. 120; no. 26; pp. 13948 - 13953
• Main Authors: Sevik, Cem, Çakır, Deniz, Gülseren, Oğuz, Peeters, François M
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.07.2016
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.6b03543

Group II–VI semiconductor honeycomb monolayers have a noncentrosymmetric crystal structure and therefore are expected to be important for nano piezoelectric device applications. This motivated us to perform first-principles calculations based on density functional theory to unveil the piezoelectric properties (i.e., piezoelectric stress (e 11) and piezoelectric strain (d 11) coefficients) of these monolayer materials with chemical formula MX (where M = Be, Mg, Ca, Sr, Ba, Zr, Cd and X = S, Se, Te). We found that these two-dimensional materials have peculiar piezoelectric properties with d 11 coefficients 1 order of magnitude larger than those of commercially utilized bulk materials. A clear trend in their piezoelectric properties emerges, which originates mainly from their mechanical properties. We establish a simple correlation between the piezoelectric strain coefficients and the physical properties, as the natural elemental polarizabilities, the Bader charges, and lattice constants of the individual M/X atoms and MX monolayers.