A Tersoff-based interatomic potential for wurtzite AlN

Aluminum nitride (AlN) is a popular buffer layer and interlayer. The understanding of how AlN serves as a wetting and fracture-mitigating layer relies on molecular pictures of the AlN layer and the interfaces. However, molecular dynamics (MD) simulation studies on AlN system, particularly on its wurtzite phase, have been limited. This is because most existing interatomic force fields of AlN target the less common zinc blende phase. Here, we report a new Tersoff-based AlN force field for its wurtzite structure. This potential has been extensively tested in terms of lattice parameters, bulk modulus, cohesive energy, and heat capacity. In addition, thermal expansion coefficient (TEC) of wurtzite AlN, a key property to precisely model heterostructures, has been calculated using MD method. The value of 2.66 x 10(-6) K(-1) calculated at 300 K for TEC is in excellent agreement with the reported experimental value. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim