Realizing giant ferroelectricity in stable wz-Al1−xBxN alloys by controlling the microstructure and elastic constant
Jie Su, Zhengmao Xiao, Xinhao Chen, Yong Huang, Zhenhua Lin, Jingjing Chang, Jincheng Zhang, Yue Hao
Abstract
The emerged wurtzite (wz) Al 1− x B x N alloy has drawn increasing attention due to its superior ferroelectricity and excellent compatibility with microelectronics. We find that the stability and ferroelectric switching pathways of wz-Al 1− x B x N alloys are affected by the orbital contribution, covalent bond strength, and elastic constant C 14 . As the concentration of B increases, the internal parameter u decreases while the elastic constant C 14 increases, leading to an increase in spontaneous polarization and a decrease in the polarization switching barrier. The spontaneous polarization, polarization switching barrier, and band gap of wz-Al 1− x B x N alloy can be further improved through the application of strain in a specific direction, resulting in a giant ferroelectricity. Additionally, the phase transformation of the wz-Al 1− x B x N alloy induced by the increasing B composition can be regarded as a sequential process involving shrinkage, rotation, and deformation of tetrahedron. These findings give a deep understanding of the ferroelectric wz-Al 1− x B x N alloy, and provide a guideline for designing a high-performance ferroelectric wz-Al 1− x B x N alloy.