Phonon and electronic properties of semiconducting silicon nitride bilayers

• Published in: arXiv.org
• Main Authors: Li, Jiesen, Lin, Wanxing, Shi, Junjun, Zhu, Feng, Xie, Haiwen, Dao-Xin Yao
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 31.03.2024
• Subjects: Beta phase; Bilayers; Covalent bonds; First principles; Orbitals; Phases; Phonons; Physics - Materials Science; Silicon nitride
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1707.02819

The two-dimensional (2D) IV-V semiconductors have attracted much attention due to their fascinating electronic and optical properties. In this work, we predicted three phases of silicon nitrides, denoted \(\alpha\)-Si\(_{2}\)N\(_{2}\), \(\beta\)-Si\(_{2}\)N\(_{2}\), and \(\gamma\)-Si\(_{4}\)N\(_{4}\), respectively. Both \(\alpha\)-Si\(_{2}\)N\(_{2}\) and \(\beta\)-Si\(_{2}\)N\(_{2}\) consist of two buckled SiN sheets, and \(\gamma\)-Si\(_{4}\)N\(_{4}\) consists of two puckered SiN sheets. It is challenging to transform between \(\alpha\)-Si\(_{2}\)N\(_{2}\) and \(\beta\)-Si\(_{2}\)N\(_{2}\) because of the high energy barrier. The three dynamically stable bilayers are semiconductors with fundamental indirect band gaps from 0.25 eV to 2.92 eV. As expected, only the s and p orbitals contribute to the electronic states, and the pz orbitals dominate near the Fermi level. Furthermore, insulator-metal transitions occur in \(\alpha\)-Si\(_{2}\)N\(_{2}\) and \(\beta\)-Si\(_{2}\)N\(_{2}\) under the biaxial strain of 16%. These materials perhaps have potential applications in microelectronics and spintronics.