Tuning the electronic and piezoelectric properties of Janus Ga2XY (X/YS, Se, Te) monolayers: A first-principles calculation

• Published in: Materials science in semiconductor processing 2024-08, Vol.178, p.108367, Article 108367
• Main Authors: Yao, Shida, Ma, Xinguo, Huang, Chuyun, Guo, Youyou, Ren, Yijing, Ma, Nan
• Format: Article
• Language: English
• Subjects: First-principles; Janus materials; Piezoelectricity; Strain
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2024.108367

The quest for novel materials exhibiting significant piezoelectricity remains imminent. Herein, the piezoelectricity of Janus Ga2XY (X/YS, Se, Te) monolayers has been investigated by DFT calculation. The results show that in-plane piezoelectric coefficients d11 of Ga2SSe, Ga2STe, Ga2SeTe are 3.08, 4.76, 3.55 p.m./V, and out-of-plane piezoelectric coefficients d31 are 0.14, 0.45, 0.33 pm/V. In addition, the vertical mirror asymmetry and different charge distributions lead to large piezoelectric properties of Ga2STe. Notably, strain can effectively regulate the piezoelectric properties of Janus Ga2XY monolayers. Under tensile strain, the piezoelectric stress coefficients (e11) of Ga2XY increase and the elastic stiffness coefficients (C11+C12, C11–C12) decrease, resulting in significant piezoelectric coefficients (d11 and d31), which can be attributed to an increase in Born effective charge Zxx* and a decrease in the bond force. The results establish a theoretical foundation for the application of novel 2D Janus Ga2XY monolayers in piezoelectric devices. Variation of piezoelectric coefficient of Ga2XY (X/YS, Se, Te) under −4%–4% biaxial strain. [Display omitted] •The Janus Ga2XY (X/YS, Se, Te) monolayers exhibit dynamical and thermal stability.•The formation of Janus structures induces piezoelectricity with d11 (3.08–4.76 pm/V) and d31 (0.14–0.45 pm/V).•The piezoelectric properties of Janus Ga2XY monolayers can be regulated by strain.•Under 4% biaxial tensile strain, Ga2STe produces large d11 (10.65 pm/V) and d31 (0.52 pm/V).