PSI - Issue 54

2

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Jelena Zagorac et al. / Procedia Structural Integrity 54 (2024) 453–459

454

1. Introduction The AlN is a thermodynamically stable compound of aluminum and nitrogen and it was first discovered in 1862 by A. Geuther along with F. Briegler and synthesized in 1877 by J.W. Mallets (Briegleb & Geuther, 1862). Nevertheless, it took more than 100 years for scientists to discover its full potential. The AlN crystallizes in three different crystal systems. At ambient conditions, the AlN crystallizes in the hexagonal crystal structure (wurtzite type), where the aluminum atoms form a close-packed hexagonal lattice with nitrogen atoms occupying half of the tetrahedral interstices of the crystal lattice (Kasap & Capper, 2017, Zagorac & Zagorac, 2023). Additionally, there are two metastable phases with cubic symmetry: the cubic ZnS sphalerite (zinc-blende) structure and the NaCl rock-salt type structure (Zagorac & Zagorac, 2023, Kasap & Capper, 2017). Thus, the compound is predominantly covalently bonded, however, with a proportion of 45% ionic bond. The boron nitride first synthesized in 1842 by W. H. Balmain in the first place is known for its very high hardness, chemical and thermal stability, high-temperature resistance, and very good electrical insulation qualities when compared with similar compounds (Balmain, 1842, Naclerio & Kidambi, 2023, Liu et al. , 2019). The BN crystallizes in several different crystal systems, of which most known are hexagonal, cubic, and wurtzite-type structures, also known as h-BN, c-BN, and w-BN respectively (Liu et al. , 2019, Cazorla & Gould, 2019). The most stable structure of the BN is the soft, hexagonal (h-BN) form which has broad applications in various fields, such as 2D material, lubricant material, semiconductor material, and many others (Arenal & Lopez-Bezanilla, 2015). Last but not least, the cubic form of BN and the wurtzite form of BN are known for very high hardness (only diamond has higher hardness), (Liu et al. , 2015) thermal stability, and electrical properties, which makes it a promising candidate for the semiconductor material (Dubitskiy et al. , 2005). Regarding previous studies of AlN/BN solid solution, the theoretical investigation was conducted for a 6.25 % concentration of the Al in the BN (Ahmoum et al. , 2019), BN nanotubes, nanosheets, and monolayers doped with Al (Mirzaei & Nouri, 2010, Peyghan et al. , 2013, Yu et al. , 2017) and AlN/BN thin films (S. Shanmugan, 2018, Subramani & Devarajan, 2016). Also, the structural and electronic properties of the B x Al 1-x N (x = 0.6, 0.25, 0.50 0.75) solid solution were investigated by first-principle calculations, but only for the wurtzite structure type (Zhang & Li, 2017, Ilyasov et al. , 2005). Similarly, the influence of the addition of boron on the mechanical, electronic, and thermodynamical properties was investigated theoretically focusing on the cubic phase of AlN (sphalerite structure type) (Viswanathan et al. , 2019, Teles et al. , 2002, Kumar et al. , 2015, Mbarki et al. , 2013, Riane et al. , 2008). Furthermore, the sphalerite AlN was co-doped with Y and B and investigated theoretically (Ghebouli et al. , 2011). Besides wurtzite and sphalerite structure types, the doped Al 1-x B x N system was investigated inside of possible diamond-like novel BN allotrope adopting the Pmn 2 1 space group (Yang et al. , 2017). Moreover, studies exist that investigated electronic, mechanical, and structural properties of ternary nitrides such as B x Al 1−x N solid solutions, i.e. alloys with various compositions i n the entire range of 0 ≤ x ≤ 1 (Djoudi et al. , 2012, Kumar et al. , 2015, Zhang & Li, 2017, Viswanathan et al. , 2019). Such studies demonstrated that boron in the solid solution as a substitutional atom in the AlN phase besides good electronic properties, high melting point, high chemical stability offers as well exceptional mechanical properties. Here, we present novel study on structural properties of a full scope AlN/BN compounds investigated on ab initio level of calculations. 2. Theoretical Methods Ab initio calculations are based on the linear combination of the atomic orbitals (LCAO) within the density functional theory (DFT) as implemented in the Crystal17 code (Dovesi et al. , 2005, Dovesi et al. , 2018). To investigate structural properties it is important to study the energy landscape of chemical systems at standard and extreme conditions (Schön, 2021, Schön, 2023, Zagorac, Zagorac, Doll , et al. , 2019, Pejić et al. , 2022). Initial structures were obtained from the Inorganic Crystal Structure Database (ICSD) (Bergerhoff & Brown, 1987, Zagorac, Mueller , et al. , 2019, Allmann & Hinek, 2007), while each of the investigated phases and compositions is generated using the