Diffusion Monte Carlo Study on Relative Stabilities of Boron Nitride Polymorphs

Although Boron nitride (BN) is a well-known compound widely used for engineering and scientific purposes, the phase stability of its polymorphs, one most fundamental properties, still under debate. The ab initio determination ground state BN such as hexagonal zinc-blende, difficult because elusive Van der Waals interaction, which plays decisive role in some making quantitative prediction highly challenging. Hence, despite multiple theoretical studies, there has been no consensus on yet, primarily due to contradicting reports. In this study, we apply state-of-the-art framework - fixed-node diffusion Monte Carlo (FNDMC), four well known namely hexagonal, rhombohedral, wurtzite, zinc-blende BNs. Our FNDMC calculations show that hBN thermodynamically stable among polymorphs at 0 K 300K. This result agrees with experimental data Corrigan~{\it et al.} Fukunaga. conclusions are consistent those obtained using other high-level methods, coupled cluster. We demonstrate powerful method address exhibit bonds various forms. It also provides valuable information, like reliable reference energies, when missing or access. findings should promote application van materials.