First-principles insights into the ferroelectric, dielectric, and piezoelectric properties of polar Pca21 SbN

Binary nitride semiconductors have important applications in the industrial and technological fields. In this work, based on the recently reported metastable $Pca{2}_{1}$ phase of SbN, we investigated its structural stability, ferroelectric, dielectric, and piezoelectric properties using first-principles calculations. Our results indicate that the metastable SbN can be stabilized with a small hydrostatic pressure. Furthermore, we theoretically confirmed the presence of ferroelectricity in SbN, driven by stereochemically active ${\mathrm{Sb}}^{3+}\phantom{\rule{4pt}{0ex}}5{s}^{2}$ lone pair electrons. The estimated polarization value is close to that of traditional ${\mathrm{PbTiO}}_{3}$. Moreover, SbN exhibits anisotropic dielectric constants, particularly in the ionic contribution part, primarily arising from the distinct mode-effective charges along different directions. In addition, SbN also exhibits a large ${d}_{33}$ piezoelectric response, which is approximately four times larger than that of wurtzite-type AlN. The large ${d}_{33}$ value is originated from the enhanced sensitivity of the atomic coordinates to the external strain $\frac{\mathrm{d}{u}_{3}}{\mathrm{d}{\ensuremath{\eta}}_{3}}$ and softening of the elastic constant ${C}_{33}$. Therefore, our study provides meaningful theoretical guidance for the future experimental synthesis of stable binary nitride semiconductors and their device applications.